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Cosmos/Users/Orvid/Orvid.Compression/Streams/Deflate.cs

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//
// Copyright (C) 2001 Mike Krueger
// Copyright (C) 2004 John Reilly
//
// This file was translated from java, it was part of the GNU Classpath
// Copyright (C) 2001 Free Software Foundation, Inc.
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
// Linking this library statically or dynamically with other modules is
// making a combined work based on this library. Thus, the terms and
// conditions of the GNU General Public License cover the whole
// combination.
//
// As a special exception, the copyright holders of this library give you
// permission to link this library with independent modules to produce an
// executable, regardless of the license terms of these independent
// modules, and to copy and distribute the resulting executable under
// terms of your choice, provided that you also meet, for each linked
// independent module, the terms and conditions of the license of that
// module. An independent module is a module which is not derived from
// or based on this library. If you modify this library, you may extend
// this exception to your version of the library, but you are not
// obligated to do so. If you do not wish to do so, delete this
// exception statement from your version.
// HISTORY
// 11-08-2009 GeoffHart T9121 Added Multi-member gzip support
using System;
using System.IO;
using Orvid.Compression.Checksums;
namespace Orvid.Compression.Streams
{
#region DeflaterInputStream
/// <summary>
/// This filter stream is used to decompress data compressed using the "deflate"
/// format. The "deflate" format is described in RFC 1951.
///
/// This stream may form the basis for other decompression filters, such
/// as the <see cref="ICSharpCode.SharpZipLib.GZip.GZipInputStream">GZipInputStream</see>.
///
/// Author of the original java version : John Leuner.
/// </summary>
public class DeflaterInputStream : Stream
{
#region Constructors
/// <summary>
/// Create an DeflaterInputStream with the default decompressor
/// and a default buffer size of 4KB.
/// </summary>
/// <param name = "baseInputStream">
/// The InputStream to read bytes from
/// </param>
public DeflaterInputStream(Stream baseInputStream)
: this(baseInputStream, new Inflater(), 4096)
{
}
/// <summary>
/// Create an DeflaterInputStream with the specified decompressor
/// and the specified buffer size.
/// </summary>
/// <param name = "baseInputStream">
/// The InputStream to read bytes from
/// </param>
/// <param name = "inflater">
/// The decompressor to use
/// </param>
/// <param name = "bufferSize">
/// Size of the buffer to use
/// </param>
internal DeflaterInputStream(Stream baseInputStream, Inflater inflater, int bufferSize)
{
if (baseInputStream == null)
{
throw new ArgumentNullException("baseInputStream");
}
if (inflater == null)
{
throw new ArgumentNullException("inflater");
}
if (bufferSize <= 0)
{
throw new ArgumentOutOfRangeException("bufferSize");
}
this.baseInputStream = baseInputStream;
this.inf = inflater;
inputBuffer = new InflaterInputBuffer(baseInputStream, bufferSize);
}
#endregion
/// <summary>
/// Get/set flag indicating ownership of underlying stream.
/// When the flag is true <see cref="Close"/> will close the underlying stream also.
/// </summary>
/// <remarks>
/// The default value is true.
/// </remarks>
public bool IsStreamOwner
{
get { return isStreamOwner; }
set { isStreamOwner = value; }
}
/// <summary>
/// Skip specified number of bytes of uncompressed data
/// </summary>
/// <param name ="count">
/// Number of bytes to skip
/// </param>
/// <returns>
/// The number of bytes skipped, zero if the end of
/// stream has been reached
/// </returns>
/// <exception cref="ArgumentOutOfRangeException">
/// <paramref name="count">The number of bytes</paramref> to skip is less than or equal to zero.
/// </exception>
public long Skip(long count)
{
if (count <= 0)
{
throw new ArgumentOutOfRangeException("count");
}
// v0.80 Skip by seeking if underlying stream supports it...
if (baseInputStream.CanSeek)
{
baseInputStream.Seek(count, SeekOrigin.Current);
return count;
}
else
{
int length = 2048;
if (count < length)
{
length = (int)count;
}
byte[] tmp = new byte[length];
int readCount = 1;
long toSkip = count;
while ((toSkip > 0) && (readCount > 0))
{
if (toSkip < length)
{
length = (int)toSkip;
}
readCount = baseInputStream.Read(tmp, 0, length);
toSkip -= readCount;
}
return count - toSkip;
}
}
/// <summary>
/// Returns 0 once the end of the stream (EOF) has been reached.
/// Otherwise returns 1.
/// </summary>
public virtual int Available
{
get
{
return inf.IsFinished ? 0 : 1;
}
}
/// <summary>
/// Fills the buffer with more data to decompress.
/// </summary>
/// <exception cref="SharpZipBaseException">
/// Stream ends early
/// </exception>
protected void Fill()
{
// Protect against redundant calls
if (inputBuffer.Available <= 0)
{
inputBuffer.Fill();
if (inputBuffer.Available <= 0)
{
throw new Exception("Unexpected EOF");
}
}
inputBuffer.SetInflaterInput(inf);
}
#region Stream Overrides
/// <summary>
/// Gets a value indicating whether the current stream supports reading
/// </summary>
public override bool CanRead
{
get
{
return baseInputStream.CanRead;
}
}
/// <summary>
/// Gets a value of false indicating seeking is not supported for this stream.
/// </summary>
public override bool CanSeek
{
get
{
return false;
}
}
/// <summary>
/// Gets a value of false indicating that this stream is not writeable.
/// </summary>
public override bool CanWrite
{
get
{
return false;
}
}
/// <summary>
/// A value representing the length of the stream in bytes.
/// </summary>
public override long Length
{
get
{
return inputBuffer.RawLength;
}
}
/// <summary>
/// The current position within the stream.
/// Throws a NotSupportedException when attempting to set the position
/// </summary>
/// <exception cref="NotSupportedException">Attempting to set the position</exception>
public override long Position
{
get
{
return baseInputStream.Position;
}
set
{
throw new NotSupportedException("InflaterInputStream Position not supported");
}
}
/// <summary>
/// Flushes the baseInputStream
/// </summary>
public override void Flush()
{
baseInputStream.Flush();
}
/// <summary>
/// Sets the position within the current stream
/// Always throws a NotSupportedException
/// </summary>
/// <param name="offset">The relative offset to seek to.</param>
/// <param name="origin">The <see cref="SeekOrigin"/> defining where to seek from.</param>
/// <returns>The new position in the stream.</returns>
/// <exception cref="NotSupportedException">Any access</exception>
public override long Seek(long offset, SeekOrigin origin)
{
throw new NotSupportedException("Seek not supported");
}
/// <summary>
/// Set the length of the current stream
/// Always throws a NotSupportedException
/// </summary>
/// <param name="value">The new length value for the stream.</param>
/// <exception cref="NotSupportedException">Any access</exception>
public override void SetLength(long value)
{
throw new NotSupportedException("InflaterInputStream SetLength not supported");
}
/// <summary>
/// Writes a sequence of bytes to stream and advances the current position
/// This method always throws a NotSupportedException
/// </summary>
/// <param name="buffer">Thew buffer containing data to write.</param>
/// <param name="offset">The offset of the first byte to write.</param>
/// <param name="count">The number of bytes to write.</param>
/// <exception cref="NotSupportedException">Any access</exception>
public override void Write(byte[] buffer, int offset, int count)
{
throw new NotSupportedException("InflaterInputStream Write not supported");
}
/// <summary>
/// Writes one byte to the current stream and advances the current position
/// Always throws a NotSupportedException
/// </summary>
/// <param name="value">The byte to write.</param>
/// <exception cref="NotSupportedException">Any access</exception>
public override void WriteByte(byte value)
{
throw new NotSupportedException("InflaterInputStream WriteByte not supported");
}
/// <summary>
/// Entry point to begin an asynchronous write. Always throws a NotSupportedException.
/// </summary>
/// <param name="buffer">The buffer to write data from</param>
/// <param name="offset">Offset of first byte to write</param>
/// <param name="count">The maximum number of bytes to write</param>
/// <param name="callback">The method to be called when the asynchronous write operation is completed</param>
/// <param name="state">A user-provided object that distinguishes this particular asynchronous write request from other requests</param>
/// <returns>An <see cref="System.IAsyncResult">IAsyncResult</see> that references the asynchronous write</returns>
/// <exception cref="NotSupportedException">Any access</exception>
public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
{
throw new NotSupportedException("InflaterInputStream BeginWrite not supported");
}
/// <summary>
/// Closes the input stream. When <see cref="IsStreamOwner"></see>
/// is true the underlying stream is also closed.
/// </summary>
public override void Close()
{
if (!isClosed)
{
isClosed = true;
if (isStreamOwner)
{
baseInputStream.Close();
}
}
}
/// <summary>
/// Reads decompressed data into the provided buffer byte array
/// </summary>
/// <param name ="buffer">
/// The array to read and decompress data into
/// </param>
/// <param name ="offset">
/// The offset indicating where the data should be placed
/// </param>
/// <param name ="count">
/// The number of bytes to decompress
/// </param>
/// <returns>The number of bytes read. Zero signals the end of stream</returns>
/// <exception cref="SharpZipBaseException">
/// Inflater needs a dictionary
/// </exception>
public override int Read(byte[] buffer, int offset, int count)
{
if (inf.IsNeedingDictionary)
{
throw new Exception("Need a dictionary");
}
int remainingBytes = count;
while (true)
{
int bytesRead = inf.Inflate(buffer, offset, remainingBytes);
offset += bytesRead;
remainingBytes -= bytesRead;
if (remainingBytes == 0 || inf.IsFinished)
{
break;
}
if (inf.IsNeedingInput)
{
Fill();
}
else if (bytesRead == 0)
{
throw new Exception("Dont know what to do");
}
}
return count - remainingBytes;
}
#endregion
#region Instance Fields
/// <summary>
/// Decompressor for this stream
/// </summary>
internal Inflater inf;
/// <summary>
/// <see cref="InflaterInputBuffer">Input buffer</see> for this stream.
/// </summary>
internal InflaterInputBuffer inputBuffer;
/// <summary>
/// Base stream the inflater reads from.
/// </summary>
private Stream baseInputStream;
/// <summary>
/// The compressed size
/// </summary>
protected long csize;
/// <summary>
/// Flag indicating wether this instance has been closed or not.
/// </summary>
bool isClosed;
/// <summary>
/// Flag indicating wether this instance is designated the stream owner.
/// When closing if this flag is true the underlying stream is closed.
/// </summary>
bool isStreamOwner = true;
#endregion
}
#endregion
#region DeflaterOutputStream
/// <summary>
/// A special stream deflating or compressing the bytes that are
/// written to it. It uses a Deflater to perform actual deflating.<br/>
/// Authors of the original java version : Tom Tromey, Jochen Hoenicke
/// </summary>
public class DeflaterOutputStream : Stream
{
#region Constructors
/// <summary>
/// Creates a new DeflaterOutputStream with a default Deflater and default buffer size.
/// </summary>
/// <param name="baseOutputStream">
/// the output stream where deflated output should be written.
/// </param>
public DeflaterOutputStream(Stream baseOutputStream)
: this(baseOutputStream, new Deflater(), 512)
{
}
/// <summary>
/// Creates a new DeflaterOutputStream with the given Deflater and
/// buffer size.
/// </summary>
/// <param name="baseOutputStream">
/// The output stream where deflated output is written.
/// </param>
/// <param name="deflater">
/// The underlying deflater to use
/// </param>
/// <param name="bufferSize">
/// The buffer size in bytes to use when deflating (minimum value 512)
/// </param>
/// <exception cref="ArgumentOutOfRangeException">
/// bufsize is less than or equal to zero.
/// </exception>
/// <exception cref="ArgumentException">
/// baseOutputStream does not support writing
/// </exception>
/// <exception cref="ArgumentNullException">
/// deflater instance is null
/// </exception>
internal DeflaterOutputStream(Stream baseOutputStream, Deflater deflater, int bufferSize)
{
if (baseOutputStream == null)
{
throw new ArgumentNullException("baseOutputStream");
}
if (baseOutputStream.CanWrite == false)
{
throw new ArgumentException("Must support writing", "baseOutputStream");
}
if (deflater == null)
{
throw new ArgumentNullException("deflater");
}
if (bufferSize < 512)
{
throw new ArgumentOutOfRangeException("bufferSize");
}
baseOutputStream_ = baseOutputStream;
buffer_ = new byte[bufferSize];
deflater_ = deflater;
}
#endregion
#region Public API
/// <summary>
/// Finishes the stream by calling finish() on the deflater.
/// </summary>
/// <exception cref="SharpZipBaseException">
/// Not all input is deflated
/// </exception>
public virtual void Finish()
{
deflater_.Finish();
while (!deflater_.IsFinished)
{
int len = deflater_.Deflate(buffer_, 0, buffer_.Length);
if (len <= 0)
{
break;
}
baseOutputStream_.Write(buffer_, 0, len);
}
if (!deflater_.IsFinished)
{
throw new Exception("Can't deflate all input?");
}
baseOutputStream_.Flush();
}
/// <summary>
/// Get/set flag indicating ownership of the underlying stream.
/// When the flag is true <see cref="Close"></see> will close the underlying stream also.
/// </summary>
public bool IsStreamOwner
{
get { return isStreamOwner_; }
set { isStreamOwner_ = value; }
}
/// <summary>
/// Allows client to determine if an entry can be patched after its added
/// </summary>
public bool CanPatchEntries
{
get
{
return baseOutputStream_.CanSeek;
}
}
#endregion
#region Deflation Support
/// <summary>
/// Deflates everything in the input buffers. This will call
/// <code>def.deflate()</code> until all bytes from the input buffers
/// are processed.
/// </summary>
protected void Deflate()
{
while (!deflater_.IsNeedingInput)
{
int deflateCount = deflater_.Deflate(buffer_, 0, buffer_.Length);
if (deflateCount <= 0)
{
break;
}
baseOutputStream_.Write(buffer_, 0, deflateCount);
}
if (!deflater_.IsNeedingInput)
{
throw new Exception("DeflaterOutputStream can't deflate all input?");
}
}
#endregion
#region Stream Overrides
/// <summary>
/// Gets value indicating stream can be read from
/// </summary>
public override bool CanRead
{
get
{
return false;
}
}
/// <summary>
/// Gets a value indicating if seeking is supported for this stream
/// This property always returns false
/// </summary>
public override bool CanSeek
{
get
{
return false;
}
}
/// <summary>
/// Get value indicating if this stream supports writing
/// </summary>
public override bool CanWrite
{
get
{
return baseOutputStream_.CanWrite;
}
}
/// <summary>
/// Get current length of stream
/// </summary>
public override long Length
{
get
{
return baseOutputStream_.Length;
}
}
/// <summary>
/// Gets the current position within the stream.
/// </summary>
/// <exception cref="NotSupportedException">Any attempt to set position</exception>
public override long Position
{
get
{
return baseOutputStream_.Position;
}
set
{
throw new NotSupportedException("Position property not supported");
}
}
/// <summary>
/// Sets the current position of this stream to the given value. Not supported by this class!
/// </summary>
/// <param name="offset">The offset relative to the <paramref name="origin"/> to seek.</param>
/// <param name="origin">The <see cref="SeekOrigin"/> to seek from.</param>
/// <returns>The new position in the stream.</returns>
/// <exception cref="NotSupportedException">Any access</exception>
public override long Seek(long offset, SeekOrigin origin)
{
throw new NotSupportedException("DeflaterOutputStream Seek not supported");
}
/// <summary>
/// Sets the length of this stream to the given value. Not supported by this class!
/// </summary>
/// <param name="value">The new stream length.</param>
/// <exception cref="NotSupportedException">Any access</exception>
public override void SetLength(long value)
{
throw new NotSupportedException("DeflaterOutputStream SetLength not supported");
}
/// <summary>
/// Read a byte from stream advancing position by one
/// </summary>
/// <returns>The byte read cast to an int. THe value is -1 if at the end of the stream.</returns>
/// <exception cref="NotSupportedException">Any access</exception>
public override int ReadByte()
{
throw new NotSupportedException("DeflaterOutputStream ReadByte not supported");
}
/// <summary>
/// Read a block of bytes from stream
/// </summary>
/// <param name="buffer">The buffer to store read data in.</param>
/// <param name="offset">The offset to start storing at.</param>
/// <param name="count">The maximum number of bytes to read.</param>
/// <returns>The actual number of bytes read. Zero if end of stream is detected.</returns>
/// <exception cref="NotSupportedException">Any access</exception>
public override int Read(byte[] buffer, int offset, int count)
{
throw new NotSupportedException("DeflaterOutputStream Read not supported");
}
/// <summary>
/// Asynchronous reads are not supported a NotSupportedException is always thrown
/// </summary>
/// <param name="buffer">The buffer to read into.</param>
/// <param name="offset">The offset to start storing data at.</param>
/// <param name="count">The number of bytes to read</param>
/// <param name="callback">The async callback to use.</param>
/// <param name="state">The state to use.</param>
/// <returns>Returns an <see cref="IAsyncResult"/></returns>
/// <exception cref="NotSupportedException">Any access</exception>
public override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
{
throw new NotSupportedException("DeflaterOutputStream BeginRead not currently supported");
}
/// <summary>
/// Asynchronous writes arent supported, a NotSupportedException is always thrown
/// </summary>
/// <param name="buffer">The buffer to write.</param>
/// <param name="offset">The offset to begin writing at.</param>
/// <param name="count">The number of bytes to write.</param>
/// <param name="callback">The <see cref="AsyncCallback"/> to use.</param>
/// <param name="state">The state object.</param>
/// <returns>Returns an IAsyncResult.</returns>
/// <exception cref="NotSupportedException">Any access</exception>
public override IAsyncResult BeginWrite(byte[] buffer, int offset, int count, AsyncCallback callback, object state)
{
throw new NotSupportedException("BeginWrite is not supported");
}
/// <summary>
/// Flushes the stream by calling <see cref="DeflaterOutputStream.Flush">Flush</see> on the deflater and then
/// on the underlying stream. This ensures that all bytes are flushed.
/// </summary>
public override void Flush()
{
deflater_.Flush();
Deflate();
baseOutputStream_.Flush();
}
/// <summary>
/// Calls <see cref="Finish"/> and closes the underlying
/// stream when <see cref="IsStreamOwner"></see> is true.
/// </summary>
public override void Close()
{
if (!isClosed_)
{
isClosed_ = true;
try
{
Finish();
}
finally
{
if (isStreamOwner_)
{
baseOutputStream_.Close();
}
}
}
}
/// <summary>
/// Writes a single byte to the compressed output stream.
/// </summary>
/// <param name="value">
/// The byte value.
/// </param>
public override void WriteByte(byte value)
{
byte[] b = new byte[1];
b[0] = value;
Write(b, 0, 1);
}
/// <summary>
/// Writes bytes from an array to the compressed stream.
/// </summary>
/// <param name="buffer">
/// The byte array
/// </param>
/// <param name="offset">
/// The offset into the byte array where to start.
/// </param>
/// <param name="count">
/// The number of bytes to write.
/// </param>
public override void Write(byte[] buffer, int offset, int count)
{
deflater_.SetInput(buffer, offset, count);
Deflate();
}
#endregion
#region Instance Fields
/// <summary>
/// This buffer is used temporarily to retrieve the bytes from the
/// deflater and write them to the underlying output stream.
/// </summary>
byte[] buffer_;
/// <summary>
/// The deflater which is used to deflate the stream.
/// </summary>
internal Deflater deflater_;
/// <summary>
/// Base stream the deflater depends on.
/// </summary>
protected Stream baseOutputStream_;
bool isClosed_;
bool isStreamOwner_ = true;
#endregion
}
#endregion
#region InflaterHuffmanTree
internal class InflaterHuffmanTree
{
const int MAX_BITLEN = 15;
short[] tree;
public static InflaterHuffmanTree defLitLenTree;
public static InflaterHuffmanTree defDistTree;
static InflaterHuffmanTree()
{
try
{
byte[] codeLengths = new byte[288];
int i = 0;
while (i < 144)
{
codeLengths[i++] = 8;
}
while (i < 256)
{
codeLengths[i++] = 9;
}
while (i < 280)
{
codeLengths[i++] = 7;
}
while (i < 288)
{
codeLengths[i++] = 8;
}
defLitLenTree = new InflaterHuffmanTree(codeLengths);
codeLengths = new byte[32];
i = 0;
while (i < 32)
{
codeLengths[i++] = 5;
}
defDistTree = new InflaterHuffmanTree(codeLengths);
}
catch (Exception)
{
throw new Exception("InflaterHuffmanTree: static tree length illegal");
}
}
public InflaterHuffmanTree(byte[] codeLengths)
{
BuildTree(codeLengths);
}
void BuildTree(byte[] codeLengths)
{
int[] blCount = new int[MAX_BITLEN + 1];
int[] nextCode = new int[MAX_BITLEN + 1];
for (int i = 0; i < codeLengths.Length; i++)
{
int bits = codeLengths[i];
if (bits > 0)
{
blCount[bits]++;
}
}
int code = 0;
int treeSize = 512;
for (int bits = 1; bits <= MAX_BITLEN; bits++)
{
nextCode[bits] = code;
code += blCount[bits] << (16 - bits);
if (bits >= 10)
{
int start = nextCode[bits] & 0x1ff80;
int end = code & 0x1ff80;
treeSize += (end - start) >> (16 - bits);
}
}
tree = new short[treeSize];
int treePtr = 512;
for (int bits = MAX_BITLEN; bits >= 10; bits--)
{
int end = code & 0x1ff80;
code -= blCount[bits] << (16 - bits);
int start = code & 0x1ff80;
for (int i = start; i < end; i += 1 << 7)
{
tree[DeflaterHuffman.BitReverse(i)] = (short)((-treePtr << 4) | bits);
treePtr += 1 << (bits - 9);
}
}
for (int i = 0; i < codeLengths.Length; i++)
{
int bits = codeLengths[i];
if (bits == 0)
{
continue;
}
code = nextCode[bits];
int revcode = DeflaterHuffman.BitReverse(code);
if (bits <= 9)
{
do
{
tree[revcode] = (short)((i << 4) | bits);
revcode += 1 << bits;
} while (revcode < 512);
}
else
{
int subTree = tree[revcode & 511];
int treeLen = 1 << (subTree & 15);
subTree = -(subTree >> 4);
do
{
tree[subTree | (revcode >> 9)] = (short)((i << 4) | bits);
revcode += 1 << bits;
} while (revcode < treeLen);
}
nextCode[bits] = code + (1 << (16 - bits));
}
}
public int GetSymbol(StreamManipulator input)
{
int lookahead, symbol;
if ((lookahead = input.PeekBits(9)) >= 0)
{
if ((symbol = tree[lookahead]) >= 0)
{
input.DropBits(symbol & 15);
return symbol >> 4;
}
int subtree = -(symbol >> 4);
int bitlen = symbol & 15;
if ((lookahead = input.PeekBits(bitlen)) >= 0)
{
symbol = tree[subtree | (lookahead >> 9)];
input.DropBits(symbol & 15);
return symbol >> 4;
}
else
{
int bits = input.AvailableBits;
lookahead = input.PeekBits(bits);
symbol = tree[subtree | (lookahead >> 9)];
if ((symbol & 15) <= bits)
{
input.DropBits(symbol & 15);
return symbol >> 4;
}
else
{
return -1;
}
}
}
else
{
int bits = input.AvailableBits;
lookahead = input.PeekBits(bits);
symbol = tree[lookahead];
if (symbol >= 0 && (symbol & 15) <= bits)
{
input.DropBits(symbol & 15);
return symbol >> 4;
}
else
{
return -1;
}
}
}
}
#endregion
#region InflaterDynHeader
internal class InflaterDynHeader
{
const int LNUM = 0;
const int DNUM = 1;
const int BLNUM = 2;
const int BLLENS = 3;
const int LENS = 4;
const int REPS = 5;
static readonly int[] repMin = { 3, 3, 11 };
static readonly int[] repBits = { 2, 3, 7 };
static readonly int[] BL_ORDER = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
public InflaterDynHeader() { }
public bool Decode(StreamManipulator input)
{
decode_loop:
for (; ; )
{
switch (mode)
{
case LNUM:
lnum = input.PeekBits(5);
if (lnum < 0)
{
return false;
}
lnum += 257;
input.DropBits(5);
mode = DNUM;
goto case DNUM;
case DNUM:
dnum = input.PeekBits(5);
if (dnum < 0)
{
return false;
}
dnum++;
input.DropBits(5);
num = lnum + dnum;
litdistLens = new byte[num];
mode = BLNUM;
goto case BLNUM;
case BLNUM:
blnum = input.PeekBits(4);
if (blnum < 0)
{
return false;
}
blnum += 4;
input.DropBits(4);
blLens = new byte[19];
ptr = 0;
mode = BLLENS;
goto case BLLENS;
case BLLENS:
while (ptr < blnum)
{
int len = input.PeekBits(3);
if (len < 0)
{
return false;
}
input.DropBits(3);
blLens[BL_ORDER[ptr]] = (byte)len;
ptr++;
}
blTree = new InflaterHuffmanTree(blLens);
blLens = null;
ptr = 0;
mode = LENS;
goto case LENS;
case LENS:
{
int symbol;
while (((symbol = blTree.GetSymbol(input)) & ~15) == 0)
{
litdistLens[ptr++] = lastLen = (byte)symbol;
if (ptr == num)
{
return true;
}
}
if (symbol < 0)
{
return false;
}
if (symbol >= 17)
{
lastLen = 0;
}
else
{
if (ptr == 0)
{
throw new Exception();
}
}
repSymbol = symbol - 16;
}
mode = REPS;
goto case REPS;
case REPS:
{
int bits = repBits[repSymbol];
int count = input.PeekBits(bits);
if (count < 0)
{
return false;
}
input.DropBits(bits);
count += repMin[repSymbol];
if (ptr + count > num)
{
throw new Exception();
}
while (count-- > 0)
{
litdistLens[ptr++] = lastLen;
}
if (ptr == num)
{
return true;
}
}
mode = LENS;
goto decode_loop;
}
}
}
public InflaterHuffmanTree BuildLitLenTree()
{
byte[] litlenLens = new byte[lnum];
Array.Copy(litdistLens, 0, litlenLens, 0, lnum);
return new InflaterHuffmanTree(litlenLens);
}
public InflaterHuffmanTree BuildDistTree()
{
byte[] distLens = new byte[dnum];
Array.Copy(litdistLens, lnum, distLens, 0, dnum);
return new InflaterHuffmanTree(distLens);
}
byte[] blLens;
byte[] litdistLens;
InflaterHuffmanTree blTree;
int mode;
int lnum, dnum, blnum, num;
int repSymbol;
byte lastLen;
int ptr;
}
#endregion
#region StreamManipulator
internal class StreamManipulator
{
public StreamManipulator() { }
public int PeekBits(int bitCount)
{
if (bitsInBuffer_ < bitCount)
{
if (windowStart_ == windowEnd_)
{
return -1;
}
buffer_ |= (uint)((window_[windowStart_++] & 0xff |
(window_[windowStart_++] & 0xff) << 8) << bitsInBuffer_);
bitsInBuffer_ += 16;
}
return (int)(buffer_ & ((1 << bitCount) - 1));
}
public void DropBits(int bitCount)
{
buffer_ >>= bitCount;
bitsInBuffer_ -= bitCount;
}
public int GetBits(int bitCount)
{
int bits = PeekBits(bitCount);
if (bits >= 0)
{
DropBits(bitCount);
}
return bits;
}
public int AvailableBits
{
get
{
return bitsInBuffer_;
}
}
public int AvailableBytes
{
get
{
return windowEnd_ - windowStart_ + (bitsInBuffer_ >> 3);
}
}
public void SkipToByteBoundary()
{
buffer_ >>= (bitsInBuffer_ & 7);
bitsInBuffer_ &= ~7;
}
public bool IsNeedingInput
{
get
{
return windowStart_ == windowEnd_;
}
}
public int CopyBytes(byte[] output, int offset, int length)
{
if (length < 0)
{
throw new ArgumentOutOfRangeException("length");
}
if ((bitsInBuffer_ & 7) != 0)
{
throw new InvalidOperationException("Bit buffer is not byte aligned!");
}
int count = 0;
while ((bitsInBuffer_ > 0) && (length > 0))
{
output[offset++] = (byte)buffer_;
buffer_ >>= 8;
bitsInBuffer_ -= 8;
length--;
count++;
}
if (length == 0)
{
return count;
}
int avail = windowEnd_ - windowStart_;
if (length > avail)
{
length = avail;
}
System.Array.Copy(window_, windowStart_, output, offset, length);
windowStart_ += length;
if (((windowStart_ - windowEnd_) & 1) != 0)
{
buffer_ = (uint)(window_[windowStart_++] & 0xff);
bitsInBuffer_ = 8;
}
return count + length;
}
public void Reset()
{
buffer_ = 0;
windowStart_ = windowEnd_ = bitsInBuffer_ = 0;
}
public void SetInput(byte[] buffer, int offset, int count)
{
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
if (offset < 0)
{
throw new ArgumentOutOfRangeException("offset", "Cannot be negative");
}
if (count < 0)
{
throw new ArgumentOutOfRangeException("count", "Cannot be negative");
}
if (windowStart_ < windowEnd_)
{
throw new InvalidOperationException("Old input was not completely processed");
}
int end = offset + count;
if ((offset > end) || (end > buffer.Length))
{
throw new ArgumentOutOfRangeException("count");
}
if ((count & 1) != 0)
{
buffer_ |= (uint)((buffer[offset++] & 0xff) << bitsInBuffer_);
bitsInBuffer_ += 8;
}
window_ = buffer;
windowStart_ = offset;
windowEnd_ = end;
}
private byte[] window_;
private int windowStart_;
private int windowEnd_;
private uint buffer_;
private int bitsInBuffer_;
}
#endregion
#region PendingBuffer
internal class PendingBuffer
{
#region Instance Fields
byte[] buffer_;
int start;
int end;
uint bits;
int bitCount;
#endregion
#region Constructors
public PendingBuffer() : this(4096)
{
}
public PendingBuffer(int bufferSize)
{
buffer_ = new byte[bufferSize];
}
#endregion
public void Reset()
{
start = end = bitCount = 0;
}
public void WriteByte(int value)
{
buffer_[end++] = unchecked((byte)value);
}
public void WriteShort(int value)
{
buffer_[end++] = unchecked((byte)value);
buffer_[end++] = unchecked((byte)(value >> 8));
}
public void WriteInt(int value)
{
buffer_[end++] = unchecked((byte)value);
buffer_[end++] = unchecked((byte)(value >> 8));
buffer_[end++] = unchecked((byte)(value >> 16));
buffer_[end++] = unchecked((byte)(value >> 24));
}
public void WriteBlock(byte[] block, int offset, int length)
{
System.Array.Copy(block, offset, buffer_, end, length);
end += length;
}
public int BitCount
{
get
{
return bitCount;
}
}
public void AlignToByte()
{
if (bitCount > 0)
{
buffer_[end++] = unchecked((byte)bits);
if (bitCount > 8)
{
buffer_[end++] = unchecked((byte)(bits >> 8));
}
}
bits = 0;
bitCount = 0;
}
public void WriteBits(int b, int count)
{
bits |= (uint)(b << bitCount);
bitCount += count;
if (bitCount >= 16)
{
buffer_[end++] = unchecked((byte)bits);
buffer_[end++] = unchecked((byte)(bits >> 8));
bits >>= 16;
bitCount -= 16;
}
}
public void WriteShortMSB(int s)
{
buffer_[end++] = unchecked((byte)(s >> 8));
buffer_[end++] = unchecked((byte)s);
}
public bool IsFlushed
{
get
{
return end == 0;
}
}
public int Flush(byte[] output, int offset, int length)
{
if (bitCount >= 8)
{
buffer_[end++] = unchecked((byte)bits);
bits >>= 8;
bitCount -= 8;
}
if (length > end - start)
{
length = end - start;
System.Array.Copy(buffer_, start, output, offset, length);
start = 0;
end = 0;
}
else
{
System.Array.Copy(buffer_, start, output, offset, length);
start += length;
}
return length;
}
public byte[] ToByteArray()
{
byte[] result = new byte[end - start];
System.Array.Copy(buffer_, start, result, 0, result.Length);
start = 0;
end = 0;
return result;
}
}
#endregion
#region DeflaterPending
internal class DeflaterPending : PendingBuffer
{
public DeflaterPending() : base(DeflaterConstants.PENDING_BUF_SIZE)
{
}
}
#endregion
#region DeflaterHuffman
/// <summary>
/// This is the DeflaterHuffman class.
///
/// This class is <i>not</i> thread safe. This is inherent in the API, due
/// to the split of Deflate and SetInput.
///
/// author of the original java version : Jochen Hoenicke
/// </summary>
internal class DeflaterHuffman
{
const int BUFSIZE = 1 << (DeflaterConstants.DEFAULT_MEM_LEVEL + 6);
const int LITERAL_NUM = 286;
const int DIST_NUM = 30;
const int BITLEN_NUM = 19;
const int REP_3_6 = 16;
const int REP_3_10 = 17;
const int REP_11_138 = 18;
const int EOF_SYMBOL = 256;
static readonly int[] BL_ORDER = { 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 };
static readonly byte[] bit4Reverse = {
0,
8,
4,
12,
2,
10,
6,
14,
1,
9,
5,
13,
3,
11,
7,
15
};
static short[] staticLCodes;
static byte[] staticLLength;
static short[] staticDCodes;
static byte[] staticDLength;
class Tree
{
#region Instance Fields
public short[] freqs;
public byte[] length;
public int minNumCodes;
public int numCodes;
short[] codes;
int[] bl_counts;
int maxLength;
DeflaterHuffman dh;
#endregion
#region Constructors
public Tree(DeflaterHuffman dh, int elems, int minCodes, int maxLength)
{
this.dh = dh;
this.minNumCodes = minCodes;
this.maxLength = maxLength;
freqs = new short[elems];
bl_counts = new int[maxLength];
}
#endregion
/// <summary>
/// Resets the internal state of the tree
/// </summary>
public void Reset()
{
for (int i = 0; i < freqs.Length; i++)
{
freqs[i] = 0;
}
codes = null;
length = null;
}
public void WriteSymbol(int code)
{
dh.pending.WriteBits(codes[code] & 0xffff, length[code]);
}
/// <summary>
/// Check that all frequencies are zero
/// </summary>
/// <exception cref="SharpZipBaseException">
/// At least one frequency is non-zero
/// </exception>
public void CheckEmpty()
{
bool empty = true;
for (int i = 0; i < freqs.Length; i++)
{
if (freqs[i] != 0)
{
empty = false;
}
}
if (!empty)
{
throw new Exception("!Empty");
}
}
/// <summary>
/// Set static codes and length
/// </summary>
/// <param name="staticCodes">new codes</param>
/// <param name="staticLengths">length for new codes</param>
public void SetStaticCodes(short[] staticCodes, byte[] staticLengths)
{
codes = staticCodes;
length = staticLengths;
}
/// <summary>
/// Build dynamic codes and lengths
/// </summary>
public void BuildCodes()
{
int numSymbols = freqs.Length;
int[] nextCode = new int[maxLength];
int code = 0;
codes = new short[freqs.Length];
for (int bits = 0; bits < maxLength; bits++)
{
nextCode[bits] = code;
code += bl_counts[bits] << (15 - bits);
}
for (int i = 0; i < numCodes; i++)
{
int bits = length[i];
if (bits > 0)
{
codes[i] = BitReverse(nextCode[bits - 1]);
nextCode[bits - 1] += 1 << (16 - bits);
}
}
}
public void BuildTree()
{
int numSymbols = freqs.Length;
int[] heap = new int[numSymbols];
int heapLen = 0;
int maxCode = 0;
for (int n = 0; n < numSymbols; n++)
{
int freq = freqs[n];
if (freq != 0)
{
int pos = heapLen++;
int ppos;
while (pos > 0 && freqs[heap[ppos = (pos - 1) / 2]] > freq)
{
heap[pos] = heap[ppos];
pos = ppos;
}
heap[pos] = n;
maxCode = n;
}
}
while (heapLen < 2)
{
int node = maxCode < 2 ? ++maxCode : 0;
heap[heapLen++] = node;
}
numCodes = Math.Max(maxCode + 1, minNumCodes);
int numLeafs = heapLen;
int[] childs = new int[4 * heapLen - 2];
int[] values = new int[2 * heapLen - 1];
int numNodes = numLeafs;
for (int i = 0; i < heapLen; i++)
{
int node = heap[i];
childs[2 * i] = node;
childs[2 * i + 1] = -1;
values[i] = freqs[node] << 8;
heap[i] = i;
}
do
{
int first = heap[0];
int last = heap[--heapLen];
int ppos = 0;
int path = 1;
while (path < heapLen)
{
if (path + 1 < heapLen && values[heap[path]] > values[heap[path + 1]])
{
path++;
}
heap[ppos] = heap[path];
ppos = path;
path = path * 2 + 1;
}
int lastVal = values[last];
while ((path = ppos) > 0 && values[heap[ppos = (path - 1) / 2]] > lastVal)
{
heap[path] = heap[ppos];
}
heap[path] = last;
int second = heap[0];
last = numNodes++;
childs[2 * last] = first;
childs[2 * last + 1] = second;
int mindepth = Math.Min(values[first] & 0xff, values[second] & 0xff);
values[last] = lastVal = values[first] + values[second] - mindepth + 1;
ppos = 0;
path = 1;
while (path < heapLen)
{
if (path + 1 < heapLen && values[heap[path]] > values[heap[path + 1]])
{
path++;
}
heap[ppos] = heap[path];
ppos = path;
path = ppos * 2 + 1;
}
while ((path = ppos) > 0 && values[heap[ppos = (path - 1) / 2]] > lastVal)
{
heap[path] = heap[ppos];
}
heap[path] = last;
} while (heapLen > 1);
if (heap[0] != childs.Length / 2 - 1)
{
throw new Exception("Heap invariant violated");
}
BuildLength(childs);
}
/// <summary>
/// Get encoded length
/// </summary>
/// <returns>Encoded length, the sum of frequencies * lengths</returns>
public int GetEncodedLength()
{
int len = 0;
for (int i = 0; i < freqs.Length; i++)
{
len += freqs[i] * length[i];
}
return len;
}
/// <summary>
/// Scan a literal or distance tree to determine the frequencies of the codes
/// in the bit length tree.
/// </summary>
public void CalcBLFreq(Tree blTree)
{
int max_count; /* max repeat count */
int min_count; /* min repeat count */
int count; /* repeat count of the current code */
int curlen = -1; /* length of current code */
int i = 0;
while (i < numCodes)
{
count = 1;
int nextlen = length[i];
if (nextlen == 0)
{
max_count = 138;
min_count = 3;
}
else
{
max_count = 6;
min_count = 3;
if (curlen != nextlen)
{
blTree.freqs[nextlen]++;
count = 0;
}
}
curlen = nextlen;
i++;
while (i < numCodes && curlen == length[i])
{
i++;
if (++count >= max_count)
{
break;
}
}
if (count < min_count)
{
blTree.freqs[curlen] += (short)count;
}
else if (curlen != 0)
{
blTree.freqs[REP_3_6]++;
}
else if (count <= 10)
{
blTree.freqs[REP_3_10]++;
}
else
{
blTree.freqs[REP_11_138]++;
}
}
}
/// <summary>
/// Write tree values
/// </summary>
/// <param name="blTree">Tree to write</param>
public void WriteTree(Tree blTree)
{
int max_count; // max repeat count
int min_count; // min repeat count
int count; // repeat count of the current code
int curlen = -1; // length of current code
int i = 0;
while (i < numCodes)
{
count = 1;
int nextlen = length[i];
if (nextlen == 0)
{
max_count = 138;
min_count = 3;
}
else
{
max_count = 6;
min_count = 3;
if (curlen != nextlen)
{
blTree.WriteSymbol(nextlen);
count = 0;
}
}
curlen = nextlen;
i++;
while (i < numCodes && curlen == length[i])
{
i++;
if (++count >= max_count)
{
break;
}
}
if (count < min_count)
{
while (count-- > 0)
{
blTree.WriteSymbol(curlen);
}
}
else if (curlen != 0)
{
blTree.WriteSymbol(REP_3_6);
dh.pending.WriteBits(count - 3, 2);
}
else if (count <= 10)
{
blTree.WriteSymbol(REP_3_10);
dh.pending.WriteBits(count - 3, 3);
}
else
{
blTree.WriteSymbol(REP_11_138);
dh.pending.WriteBits(count - 11, 7);
}
}
}
void BuildLength(int[] childs)
{
this.length = new byte[freqs.Length];
int numNodes = childs.Length / 2;
int numLeafs = (numNodes + 1) / 2;
int overflow = 0;
for (int i = 0; i < maxLength; i++)
{
bl_counts[i] = 0;
}
int[] lengths = new int[numNodes];
lengths[numNodes - 1] = 0;
for (int i = numNodes - 1; i >= 0; i--)
{
if (childs[2 * i + 1] != -1)
{
int bitLength = lengths[i] + 1;
if (bitLength > maxLength)
{
bitLength = maxLength;
overflow++;
}
lengths[childs[2 * i]] = lengths[childs[2 * i + 1]] = bitLength;
}
else
{
int bitLength = lengths[i];
bl_counts[bitLength - 1]++;
this.length[childs[2 * i]] = (byte)lengths[i];
}
}
if (overflow == 0)
{
return;
}
int incrBitLen = maxLength - 1;
do
{
while (bl_counts[--incrBitLen] == 0)
;
do
{
bl_counts[incrBitLen]--;
bl_counts[++incrBitLen]++;
overflow -= 1 << (maxLength - 1 - incrBitLen);
} while (overflow > 0 && incrBitLen < maxLength - 1);
} while (overflow > 0);
bl_counts[maxLength - 1] += overflow;
bl_counts[maxLength - 2] -= overflow;
int nodePtr = 2 * numLeafs;
for (int bits = maxLength; bits != 0; bits--)
{
int n = bl_counts[bits - 1];
while (n > 0)
{
int childPtr = 2 * childs[nodePtr++];
if (childs[childPtr + 1] == -1)
{
length[childs[childPtr]] = (byte)bits;
n--;
}
}
}
}
}
#region Instance Fields
/// <summary>
/// Pending buffer to use
/// </summary>
public DeflaterPending pending;
Tree literalTree;
Tree distTree;
Tree blTree;
// Buffer for distances
short[] d_buf;
byte[] l_buf;
int last_lit;
int extra_bits;
#endregion
static DeflaterHuffman()
{
staticLCodes = new short[LITERAL_NUM];
staticLLength = new byte[LITERAL_NUM];
int i = 0;
while (i < 144)
{
staticLCodes[i] = BitReverse((0x030 + i) << 8);
staticLLength[i++] = 8;
}
while (i < 256)
{
staticLCodes[i] = BitReverse((0x190 - 144 + i) << 7);
staticLLength[i++] = 9;
}
while (i < 280)
{
staticLCodes[i] = BitReverse((0x000 - 256 + i) << 9);
staticLLength[i++] = 7;
}
while (i < LITERAL_NUM)
{
staticLCodes[i] = BitReverse((0x0c0 - 280 + i) << 8);
staticLLength[i++] = 8;
}
staticDCodes = new short[DIST_NUM];
staticDLength = new byte[DIST_NUM];
for (i = 0; i < DIST_NUM; i++)
{
staticDCodes[i] = BitReverse(i << 11);
staticDLength[i] = 5;
}
}
/// <summary>
/// Construct instance with pending buffer
/// </summary>
/// <param name="pending">Pending buffer to use</param>
public DeflaterHuffman(DeflaterPending pending)
{
this.pending = pending;
literalTree = new Tree(this, LITERAL_NUM, 257, 15);
distTree = new Tree(this, DIST_NUM, 1, 15);
blTree = new Tree(this, BITLEN_NUM, 4, 7);
d_buf = new short[BUFSIZE];
l_buf = new byte[BUFSIZE];
}
/// <summary>
/// Reset internal state
/// </summary>
public void Reset()
{
last_lit = 0;
extra_bits = 0;
literalTree.Reset();
distTree.Reset();
blTree.Reset();
}
/// <summary>
/// Write all trees to pending buffer
/// </summary>
/// <param name="blTreeCodes">The number/rank of treecodes to send.</param>
public void SendAllTrees(int blTreeCodes)
{
blTree.BuildCodes();
literalTree.BuildCodes();
distTree.BuildCodes();
pending.WriteBits(literalTree.numCodes - 257, 5);
pending.WriteBits(distTree.numCodes - 1, 5);
pending.WriteBits(blTreeCodes - 4, 4);
for (int rank = 0; rank < blTreeCodes; rank++)
{
pending.WriteBits(blTree.length[BL_ORDER[rank]], 3);
}
literalTree.WriteTree(blTree);
distTree.WriteTree(blTree);
}
/// <summary>
/// Compress current buffer writing data to pending buffer
/// </summary>
public void CompressBlock()
{
for (int i = 0; i < last_lit; i++)
{
int litlen = l_buf[i] & 0xff;
int dist = d_buf[i];
if (dist-- != 0)
{
int lc = Lcode(litlen);
literalTree.WriteSymbol(lc);
int bits = (lc - 261) / 4;
if (bits > 0 && bits <= 5)
{
pending.WriteBits(litlen & ((1 << bits) - 1), bits);
}
int dc = Dcode(dist);
distTree.WriteSymbol(dc);
bits = dc / 2 - 1;
if (bits > 0)
{
pending.WriteBits(dist & ((1 << bits) - 1), bits);
}
}
else
{
literalTree.WriteSymbol(litlen);
}
}
literalTree.WriteSymbol(EOF_SYMBOL);
}
/// <summary>
/// Flush block to output with no compression
/// </summary>
/// <param name="stored">Data to write</param>
/// <param name="storedOffset">Index of first byte to write</param>
/// <param name="storedLength">Count of bytes to write</param>
/// <param name="lastBlock">True if this is the last block</param>
public void FlushStoredBlock(byte[] stored, int storedOffset, int storedLength, bool lastBlock)
{
pending.WriteBits((DeflaterConstants.STORED_BLOCK << 1) + (lastBlock ? 1 : 0), 3);
pending.AlignToByte();
pending.WriteShort(storedLength);
pending.WriteShort(~storedLength);
pending.WriteBlock(stored, storedOffset, storedLength);
Reset();
}
/// <summary>
/// Flush block to output with compression
/// </summary>
/// <param name="stored">Data to flush</param>
/// <param name="storedOffset">Index of first byte to flush</param>
/// <param name="storedLength">Count of bytes to flush</param>
/// <param name="lastBlock">True if this is the last block</param>
public void FlushBlock(byte[] stored, int storedOffset, int storedLength, bool lastBlock)
{
literalTree.freqs[EOF_SYMBOL]++;
literalTree.BuildTree();
distTree.BuildTree();
literalTree.CalcBLFreq(blTree);
distTree.CalcBLFreq(blTree);
blTree.BuildTree();
int blTreeCodes = 4;
for (int i = 18; i > blTreeCodes; i--)
{
if (blTree.length[BL_ORDER[i]] > 0)
{
blTreeCodes = i + 1;
}
}
int opt_len = 14 + blTreeCodes * 3 + blTree.GetEncodedLength() +
literalTree.GetEncodedLength() + distTree.GetEncodedLength() +
extra_bits;
int static_len = extra_bits;
for (int i = 0; i < LITERAL_NUM; i++)
{
static_len += literalTree.freqs[i] * staticLLength[i];
}
for (int i = 0; i < DIST_NUM; i++)
{
static_len += distTree.freqs[i] * staticDLength[i];
}
if (opt_len >= static_len)
{
opt_len = static_len;
}
if (storedOffset >= 0 && storedLength + 4 < opt_len >> 3)
{
FlushStoredBlock(stored, storedOffset, storedLength, lastBlock);
}
else if (opt_len == static_len)
{
pending.WriteBits((DeflaterConstants.STATIC_TREES << 1) + (lastBlock ? 1 : 0), 3);
literalTree.SetStaticCodes(staticLCodes, staticLLength);
distTree.SetStaticCodes(staticDCodes, staticDLength);
CompressBlock();
Reset();
}
else
{
pending.WriteBits((DeflaterConstants.DYN_TREES << 1) + (lastBlock ? 1 : 0), 3);
SendAllTrees(blTreeCodes);
CompressBlock();
Reset();
}
}
/// <summary>
/// Get value indicating if internal buffer is full
/// </summary>
/// <returns>true if buffer is full</returns>
public bool IsFull()
{
return last_lit >= BUFSIZE;
}
/// <summary>
/// Add literal to buffer
/// </summary>
/// <param name="literal">Literal value to add to buffer.</param>
/// <returns>Value indicating internal buffer is full</returns>
public bool TallyLit(int literal)
{
d_buf[last_lit] = 0;
l_buf[last_lit++] = (byte)literal;
literalTree.freqs[literal]++;
return IsFull();
}
/// <summary>
/// Add distance code and length to literal and distance trees
/// </summary>
/// <param name="distance">Distance code</param>
/// <param name="length">Length</param>
/// <returns>Value indicating if internal buffer is full</returns>
public bool TallyDist(int distance, int length)
{
d_buf[last_lit] = (short)distance;
l_buf[last_lit++] = (byte)(length - 3);
int lc = Lcode(length - 3);
literalTree.freqs[lc]++;
if (lc >= 265 && lc < 285)
{
extra_bits += (lc - 261) / 4;
}
int dc = Dcode(distance - 1);
distTree.freqs[dc]++;
if (dc >= 4)
{
extra_bits += dc / 2 - 1;
}
return IsFull();
}
/// <summary>
/// Reverse the bits of a 16 bit value.
/// </summary>
/// <param name="toReverse">Value to reverse bits</param>
/// <returns>Value with bits reversed</returns>
public static short BitReverse(int toReverse)
{
return (short)(bit4Reverse[toReverse & 0xF] << 12 |
bit4Reverse[(toReverse >> 4) & 0xF] << 8 |
bit4Reverse[(toReverse >> 8) & 0xF] << 4 |
bit4Reverse[toReverse >> 12]);
}
static int Lcode(int length)
{
if (length == 255)
{
return 285;
}
int code = 257;
while (length >= 8)
{
code += 4;
length >>= 1;
}
return code + length;
}
static int Dcode(int distance)
{
int code = 0;
while (distance >= 4)
{
code += 2;
distance >>= 1;
}
return code + distance;
}
}
#endregion
#region DeflateStrategy
/// <summary>
/// Strategies for deflater
/// </summary>
internal enum DeflateStrategy
{
/// <summary>
/// The default strategy
/// </summary>
Default = 0,
/// <summary>
/// This strategy will only allow longer string repetitions. It is
/// useful for random data with a small character set.
/// </summary>
Filtered = 1,
/// <summary>
/// This strategy will not look for string repetitions at all. It
/// only encodes with Huffman trees (which means, that more common
/// characters get a smaller encoding.
/// </summary>
HuffmanOnly = 2
}
#endregion
#region DeflaterEngine
/// <summary>
/// Low level compression engine for deflate algorithm which uses a 32K sliding window
/// with secondary compression from Huffman/Shannon-Fano codes.
/// </summary>
internal class DeflaterEngine : DeflaterConstants
{
#region Constants
const int TooFar = 4096;
#endregion
#region Constructors
/// <summary>
/// Construct instance with pending buffer
/// </summary>
/// <param name="pending">
/// Pending buffer to use
/// </param>>
public DeflaterEngine(DeflaterPending pending)
{
this.pending = pending;
huffman = new DeflaterHuffman(pending);
adler = new Adler32();
window = new byte[2 * WSIZE];
head = new short[HASH_SIZE];
prev = new short[WSIZE];
// We start at index 1, to avoid an implementation deficiency, that
// we cannot build a repeat pattern at index 0.
blockStart = strstart = 1;
}
#endregion
/// <summary>
/// Deflate drives actual compression of data
/// </summary>
/// <param name="flush">True to flush input buffers</param>
/// <param name="finish">Finish deflation with the current input.</param>
/// <returns>Returns true if progress has been made.</returns>
public bool Deflate(bool flush, bool finish)
{
bool progress;
do
{
FillWindow();
bool canFlush = flush && (inputOff == inputEnd);
switch (compressionFunction)
{
case DEFLATE_STORED:
progress = DeflateStored(canFlush, finish);
break;
case DEFLATE_FAST:
progress = DeflateFast(canFlush, finish);
break;
case DEFLATE_SLOW:
progress = DeflateSlow(canFlush, finish);
break;
default:
throw new InvalidOperationException("unknown compressionFunction");
}
} while (pending.IsFlushed && progress); // repeat while we have no pending output and progress was made
return progress;
}
/// <summary>
/// Sets input data to be deflated. Should only be called when <code>NeedsInput()</code>
/// returns true
/// </summary>
/// <param name="buffer">The buffer containing input data.</param>
/// <param name="offset">The offset of the first byte of data.</param>
/// <param name="count">The number of bytes of data to use as input.</param>
public void SetInput(byte[] buffer, int offset, int count)
{
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
if (offset < 0)
{
throw new ArgumentOutOfRangeException("offset");
}
if (count < 0)
{
throw new ArgumentOutOfRangeException("count");
}
if (inputOff < inputEnd)
{
throw new InvalidOperationException("Old input was not completely processed");
}
int end = offset + count;
/* We want to throw an ArrayIndexOutOfBoundsException early. The
* check is very tricky: it also handles integer wrap around.
*/
if ((offset > end) || (end > buffer.Length))
{
throw new ArgumentOutOfRangeException("count");
}
inputBuf = buffer;
inputOff = offset;
inputEnd = end;
}
/// <summary>
/// Determines if more <see cref="SetInput">input</see> is needed.
/// </summary>
/// <returns>Return true if input is needed via <see cref="SetInput">SetInput</see></returns>
public bool NeedsInput()
{
return (inputEnd == inputOff);
}
/// <summary>
/// Set compression dictionary
/// </summary>
/// <param name="buffer">The buffer containing the dictionary data</param>
/// <param name="offset">The offset in the buffer for the first byte of data</param>
/// <param name="length">The length of the dictionary data.</param>
public void SetDictionary(byte[] buffer, int offset, int length)
{
adler.Update(buffer, offset, length);
if (length < MIN_MATCH)
{
return;
}
if (length > MAX_DIST)
{
offset += length - MAX_DIST;
length = MAX_DIST;
}
System.Array.Copy(buffer, offset, window, strstart, length);
UpdateHash();
--length;
while (--length > 0)
{
InsertString();
strstart++;
}
strstart += 2;
blockStart = strstart;
}
/// <summary>
/// Reset internal state
/// </summary>
public void Reset()
{
huffman.Reset();
adler.Reset();
blockStart = strstart = 1;
lookahead = 0;
totalIn = 0;
prevAvailable = false;
matchLen = MIN_MATCH - 1;
for (int i = 0; i < HASH_SIZE; i++)
{
head[i] = 0;
}
for (int i = 0; i < WSIZE; i++)
{
prev[i] = 0;
}
}
/// <summary>
/// Reset Adler checksum
/// </summary>
public void ResetAdler()
{
adler.Reset();
}
/// <summary>
/// Get current value of Adler checksum
/// </summary>
public int Adler
{
get
{
return unchecked((int)adler.Value);
}
}
/// <summary>
/// Total data processed
/// </summary>
public long TotalIn
{
get
{
return totalIn;
}
}
/// <summary>
/// Get/set the <see cref="DeflateStrategy">deflate strategy</see>
/// </summary>
public DeflateStrategy Strategy
{
get
{
return strategy;
}
set
{
strategy = value;
}
}
/// <summary>
/// Set the deflate level (0-9)
/// </summary>
/// <param name="level">The value to set the level to.</param>
public void SetLevel(int level)
{
if ((level < 0) || (level > 9))
{
throw new ArgumentOutOfRangeException("level");
}
goodLength = DeflaterConstants.GOOD_LENGTH[level];
max_lazy = DeflaterConstants.MAX_LAZY[level];
niceLength = DeflaterConstants.NICE_LENGTH[level];
max_chain = DeflaterConstants.MAX_CHAIN[level];
if (DeflaterConstants.COMPR_FUNC[level] != compressionFunction)
{
switch (compressionFunction)
{
case DEFLATE_STORED:
if (strstart > blockStart)
{
huffman.FlushStoredBlock(window, blockStart,
strstart - blockStart, false);
blockStart = strstart;
}
UpdateHash();
break;
case DEFLATE_FAST:
if (strstart > blockStart)
{
huffman.FlushBlock(window, blockStart, strstart - blockStart,
false);
blockStart = strstart;
}
break;
case DEFLATE_SLOW:
if (prevAvailable)
{
huffman.TallyLit(window[strstart - 1] & 0xff);
}
if (strstart > blockStart)
{
huffman.FlushBlock(window, blockStart, strstart - blockStart, false);
blockStart = strstart;
}
prevAvailable = false;
matchLen = MIN_MATCH - 1;
break;
}
compressionFunction = COMPR_FUNC[level];
}
}
/// <summary>
/// Fill the window
/// </summary>
public void FillWindow()
{
/* If the window is almost full and there is insufficient lookahead,
* move the upper half to the lower one to make room in the upper half.
*/
if (strstart >= WSIZE + MAX_DIST)
{
SlideWindow();
}
/* If there is not enough lookahead, but still some input left,
* read in the input
*/
while (lookahead < DeflaterConstants.MIN_LOOKAHEAD && inputOff < inputEnd)
{
int more = 2 * WSIZE - lookahead - strstart;
if (more > inputEnd - inputOff)
{
more = inputEnd - inputOff;
}
System.Array.Copy(inputBuf, inputOff, window, strstart + lookahead, more);
adler.Update(inputBuf, inputOff, more);
inputOff += more;
totalIn += more;
lookahead += more;
}
if (lookahead >= MIN_MATCH)
{
UpdateHash();
}
}
void UpdateHash()
{
/*
if (DEBUGGING) {
Console.WriteLine("updateHash: "+strstart);
}
*/
ins_h = (window[strstart] << HASH_SHIFT) ^ window[strstart + 1];
}
/// <summary>
/// Inserts the current string in the head hash and returns the previous
/// value for this hash.
/// </summary>
/// <returns>The previous hash value</returns>
int InsertString()
{
short match;
int hash = ((ins_h << HASH_SHIFT) ^ window[strstart + (MIN_MATCH - 1)]) & HASH_MASK;
prev[strstart & WMASK] = match = head[hash];
head[hash] = unchecked((short)strstart);
ins_h = hash;
return match & 0xffff;
}
void SlideWindow()
{
Array.Copy(window, WSIZE, window, 0, WSIZE);
matchStart -= WSIZE;
strstart -= WSIZE;
blockStart -= WSIZE;
// Slide the hash table (could be avoided with 32 bit values
// at the expense of memory usage).
for (int i = 0; i < HASH_SIZE; ++i)
{
int m = head[i] & 0xffff;
head[i] = (short)(m >= WSIZE ? (m - WSIZE) : 0);
}
// Slide the prev table.
for (int i = 0; i < WSIZE; i++)
{
int m = prev[i] & 0xffff;
prev[i] = (short)(m >= WSIZE ? (m - WSIZE) : 0);
}
}
/// <summary>
/// Find the best (longest) string in the window matching the
/// string starting at strstart.
///
/// Preconditions:
/// <code>
/// strstart + MAX_MATCH &lt;= window.length.</code>
/// </summary>
/// <param name="curMatch"></param>
/// <returns>True if a match greater than the minimum length is found</returns>
bool FindLongestMatch(int curMatch)
{
int chainLength = this.max_chain;
int niceLength = this.niceLength;
short[] prev = this.prev;
int scan = this.strstart;
int match;
int best_end = this.strstart + matchLen;
int best_len = Math.Max(matchLen, MIN_MATCH - 1);
int limit = Math.Max(strstart - MAX_DIST, 0);
int strend = strstart + MAX_MATCH - 1;
byte scan_end1 = window[best_end - 1];
byte scan_end = window[best_end];
// Do not waste too much time if we already have a good match:
if (best_len >= this.goodLength)
{
chainLength >>= 2;
}
/* Do not look for matches beyond the end of the input. This is necessary
* to make deflate deterministic.
*/
if (niceLength > lookahead)
{
niceLength = lookahead;
}
do
{
if (window[curMatch + best_len] != scan_end ||
window[curMatch + best_len - 1] != scan_end1 ||
window[curMatch] != window[scan] ||
window[curMatch + 1] != window[scan + 1])
{
continue;
}
match = curMatch + 2;
scan += 2;
/* We check for insufficient lookahead only every 8th comparison;
* the 256th check will be made at strstart + 258.
*/
while (
window[++scan] == window[++match] &&
window[++scan] == window[++match] &&
window[++scan] == window[++match] &&
window[++scan] == window[++match] &&
window[++scan] == window[++match] &&
window[++scan] == window[++match] &&
window[++scan] == window[++match] &&
window[++scan] == window[++match] &&
(scan < strend))
{
// Do nothing
}
if (scan > best_end)
{
matchStart = curMatch;
best_end = scan;
best_len = scan - strstart;
if (best_len >= niceLength)
{
break;
}
scan_end1 = window[best_end - 1];
scan_end = window[best_end];
}
scan = strstart;
} while ((curMatch = (prev[curMatch & WMASK] & 0xffff)) > limit && --chainLength != 0);
matchLen = Math.Min(best_len, lookahead);
return matchLen >= MIN_MATCH;
}
bool DeflateStored(bool flush, bool finish)
{
if (!flush && (lookahead == 0))
{
return false;
}
strstart += lookahead;
lookahead = 0;
int storedLength = strstart - blockStart;
if ((storedLength >= DeflaterConstants.MAX_BLOCK_SIZE) || // Block is full
(blockStart < WSIZE && storedLength >= MAX_DIST) || // Block may move out of window
flush)
{
bool lastBlock = finish;
if (storedLength > DeflaterConstants.MAX_BLOCK_SIZE)
{
storedLength = DeflaterConstants.MAX_BLOCK_SIZE;
lastBlock = false;
}
huffman.FlushStoredBlock(window, blockStart, storedLength, lastBlock);
blockStart += storedLength;
return !lastBlock;
}
return true;
}
bool DeflateFast(bool flush, bool finish)
{
if (lookahead < MIN_LOOKAHEAD && !flush)
{
return false;
}
while (lookahead >= MIN_LOOKAHEAD || flush)
{
if (lookahead == 0)
{
// We are flushing everything
huffman.FlushBlock(window, blockStart, strstart - blockStart, finish);
blockStart = strstart;
return false;
}
if (strstart > 2 * WSIZE - MIN_LOOKAHEAD)
{
/* slide window, as FindLongestMatch needs this.
* This should only happen when flushing and the window
* is almost full.
*/
SlideWindow();
}
int hashHead;
if (lookahead >= MIN_MATCH &&
(hashHead = InsertString()) != 0 &&
strategy != DeflateStrategy.HuffmanOnly &&
strstart - hashHead <= MAX_DIST &&
FindLongestMatch(hashHead))
{
// longestMatch sets matchStart and matchLen
bool full = huffman.TallyDist(strstart - matchStart, matchLen);
lookahead -= matchLen;
if (matchLen <= max_lazy && lookahead >= MIN_MATCH)
{
while (--matchLen > 0)
{
++strstart;
InsertString();
}
++strstart;
}
else
{
strstart += matchLen;
if (lookahead >= MIN_MATCH - 1)
{
UpdateHash();
}
}
matchLen = MIN_MATCH - 1;
if (!full)
{
continue;
}
}
else
{
// No match found
huffman.TallyLit(window[strstart] & 0xff);
++strstart;
--lookahead;
}
if (huffman.IsFull())
{
bool lastBlock = finish && (lookahead == 0);
huffman.FlushBlock(window, blockStart, strstart - blockStart, lastBlock);
blockStart = strstart;
return !lastBlock;
}
}
return true;
}
bool DeflateSlow(bool flush, bool finish)
{
if (lookahead < MIN_LOOKAHEAD && !flush)
{
return false;
}
while (lookahead >= MIN_LOOKAHEAD || flush)
{
if (lookahead == 0)
{
if (prevAvailable)
{
huffman.TallyLit(window[strstart - 1] & 0xff);
}
prevAvailable = false;
// We are flushing everything
huffman.FlushBlock(window, blockStart, strstart - blockStart, finish);
blockStart = strstart;
return false;
}
if (strstart >= 2 * WSIZE - MIN_LOOKAHEAD)
{
/* slide window, as FindLongestMatch needs this.
* This should only happen when flushing and the window
* is almost full.
*/
SlideWindow();
}
int prevMatch = matchStart;
int prevLen = matchLen;
if (lookahead >= MIN_MATCH)
{
int hashHead = InsertString();
if (strategy != DeflateStrategy.HuffmanOnly &&
hashHead != 0 &&
strstart - hashHead <= MAX_DIST &&
FindLongestMatch(hashHead))
{
// longestMatch sets matchStart and matchLen
// Discard match if too small and too far away
if (matchLen <= 5 && (strategy == DeflateStrategy.Filtered || (matchLen == MIN_MATCH && strstart - matchStart > TooFar)))
{
matchLen = MIN_MATCH - 1;
}
}
}
// previous match was better
if ((prevLen >= MIN_MATCH) && (matchLen <= prevLen))
{
huffman.TallyDist(strstart - 1 - prevMatch, prevLen);
prevLen -= 2;
do
{
strstart++;
lookahead--;
if (lookahead >= MIN_MATCH)
{
InsertString();
}
} while (--prevLen > 0);
strstart++;
lookahead--;
prevAvailable = false;
matchLen = MIN_MATCH - 1;
}
else
{
if (prevAvailable)
{
huffman.TallyLit(window[strstart - 1] & 0xff);
}
prevAvailable = true;
strstart++;
lookahead--;
}
if (huffman.IsFull())
{
int len = strstart - blockStart;
if (prevAvailable)
{
len--;
}
bool lastBlock = (finish && (lookahead == 0) && !prevAvailable);
huffman.FlushBlock(window, blockStart, len, lastBlock);
blockStart += len;
return !lastBlock;
}
}
return true;
}
#region Instance Fields
// Hash index of string to be inserted
int ins_h;
/// <summary>
/// Hashtable, hashing three characters to an index for window, so
/// that window[index]..window[index+2] have this hash code.
/// Note that the array should really be unsigned short, so you need
/// to and the values with 0xffff.
/// </summary>
short[] head;
/// <summary>
/// <code>prev[index &amp; WMASK]</code> points to the previous index that has the
/// same hash code as the string starting at index. This way
/// entries with the same hash code are in a linked list.
/// Note that the array should really be unsigned short, so you need
/// to and the values with 0xffff.
/// </summary>
short[] prev;
int matchStart;
// Length of best match
int matchLen;
// Set if previous match exists
bool prevAvailable;
int blockStart;
/// <summary>
/// Points to the current character in the window.
/// </summary>
int strstart;
/// <summary>
/// lookahead is the number of characters starting at strstart in
/// window that are valid.
/// So window[strstart] until window[strstart+lookahead-1] are valid
/// characters.
/// </summary>
int lookahead;
/// <summary>
/// This array contains the part of the uncompressed stream that
/// is of relevance. The current character is indexed by strstart.
/// </summary>
byte[] window;
DeflateStrategy strategy;
int max_chain, max_lazy, niceLength, goodLength;
/// <summary>
/// The current compression function.
/// </summary>
int compressionFunction;
/// <summary>
/// The input data for compression.
/// </summary>
byte[] inputBuf;
/// <summary>
/// The total bytes of input read.
/// </summary>
long totalIn;
/// <summary>
/// The offset into inputBuf, where input data starts.
/// </summary>
int inputOff;
/// <summary>
/// The end offset of the input data.
/// </summary>
int inputEnd;
DeflaterPending pending;
DeflaterHuffman huffman;
/// <summary>
/// The adler checksum
/// </summary>
Adler32 adler;
#endregion
}
#endregion
#region DeflaterConstants
/// <summary>
/// This class contains constants used for deflation.
/// </summary>
internal class DeflaterConstants
{
/// <summary>
/// Set to true to enable debugging
/// </summary>
public const bool DEBUGGING = false;
/// <summary>
/// Written to Zip file to identify a stored block
/// </summary>
public const int STORED_BLOCK = 0;
/// <summary>
/// Identifies static tree in Zip file
/// </summary>
public const int STATIC_TREES = 1;
/// <summary>
/// Identifies dynamic tree in Zip file
/// </summary>
public const int DYN_TREES = 2;
/// <summary>
/// Header flag indicating a preset dictionary for deflation
/// </summary>
public const int PRESET_DICT = 0x20;
/// <summary>
/// Sets internal buffer sizes for Huffman encoding
/// </summary>
public const int DEFAULT_MEM_LEVEL = 8;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int MAX_MATCH = 258;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int MIN_MATCH = 3;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int MAX_WBITS = 15;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int WSIZE = 1 << MAX_WBITS;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int WMASK = WSIZE - 1;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int HASH_BITS = DEFAULT_MEM_LEVEL + 7;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int HASH_SIZE = 1 << HASH_BITS;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int HASH_MASK = HASH_SIZE - 1;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int HASH_SHIFT = (HASH_BITS + MIN_MATCH - 1) / MIN_MATCH;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int MIN_LOOKAHEAD = MAX_MATCH + MIN_MATCH + 1;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int MAX_DIST = WSIZE - MIN_LOOKAHEAD;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int PENDING_BUF_SIZE = 1 << (DEFAULT_MEM_LEVEL + 8);
/// <summary>
/// Internal compression engine constant
/// </summary>
public static int MAX_BLOCK_SIZE = Math.Min(65535, PENDING_BUF_SIZE - 5);
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int DEFLATE_STORED = 0;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int DEFLATE_FAST = 1;
/// <summary>
/// Internal compression engine constant
/// </summary>
public const int DEFLATE_SLOW = 2;
/// <summary>
/// Internal compression engine constant
/// </summary>
public static int[] GOOD_LENGTH = { 0, 4, 4, 4, 4, 8, 8, 8, 32, 32 };
/// <summary>
/// Internal compression engine constant
/// </summary>
public static int[] MAX_LAZY = { 0, 4, 5, 6, 4, 16, 16, 32, 128, 258 };
/// <summary>
/// Internal compression engine constant
/// </summary>
public static int[] NICE_LENGTH = { 0, 8, 16, 32, 16, 32, 128, 128, 258, 258 };
/// <summary>
/// Internal compression engine constant
/// </summary>
public static int[] MAX_CHAIN = { 0, 4, 8, 32, 16, 32, 128, 256, 1024, 4096 };
/// <summary>
/// Internal compression engine constant
/// </summary>
public static int[] COMPR_FUNC = { 0, 1, 1, 1, 1, 2, 2, 2, 2, 2 };
}
#endregion
#region Deflater
/// <summary>
/// This is the Deflater class. The deflater class compresses input
/// with the deflate algorithm described in RFC 1951. It has several
/// compression levels and three different strategies described below.
///
/// This class is <i>not</i> thread safe. This is inherent in the API, due
/// to the split of deflate and setInput.
///
/// author of the original java version : Jochen Hoenicke
/// </summary>
internal class Deflater
{
#region Deflater Documentation
/*
* The Deflater can do the following state transitions:
*
* (1) -> INIT_STATE ----> INIT_FINISHING_STATE ---.
* / | (2) (5) |
* / v (5) |
* (3)| SETDICT_STATE ---> SETDICT_FINISHING_STATE |(3)
* \ | (3) | ,--------'
* | | | (3) /
* v v (5) v v
* (1) -> BUSY_STATE ----> FINISHING_STATE
* | (6)
* v
* FINISHED_STATE
* \_____________________________________/
* | (7)
* v
* CLOSED_STATE
*
* (1) If we should produce a header we start in INIT_STATE, otherwise
* we start in BUSY_STATE.
* (2) A dictionary may be set only when we are in INIT_STATE, then
* we change the state as indicated.
* (3) Whether a dictionary is set or not, on the first call of deflate
* we change to BUSY_STATE.
* (4) -- intentionally left blank -- :)
* (5) FINISHING_STATE is entered, when flush() is called to indicate that
* there is no more INPUT. There are also states indicating, that
* the header wasn't written yet.
* (6) FINISHED_STATE is entered, when everything has been flushed to the
* internal pending output buffer.
* (7) At any time (7)
*
*/
#endregion
#region Public Constants
/// <summary>
/// The best and slowest compression level. This tries to find very
/// long and distant string repetitions.
/// </summary>
public const int BEST_COMPRESSION = 9;
/// <summary>
/// The worst but fastest compression level.
/// </summary>
public const int BEST_SPEED = 1;
/// <summary>
/// The default compression level.
/// </summary>
public const int DEFAULT_COMPRESSION = -1;
/// <summary>
/// This level won't compress at all but output uncompressed blocks.
/// </summary>
public const int NO_COMPRESSION = 0;
/// <summary>
/// The compression method. This is the only method supported so far.
/// There is no need to use this constant at all.
/// </summary>
public const int DEFLATED = 8;
#endregion
#region Local Constants
private const int IS_SETDICT = 0x01;
private const int IS_FLUSHING = 0x04;
private const int IS_FINISHING = 0x08;
private const int INIT_STATE = 0x00;
private const int SETDICT_STATE = 0x01;
// private static int INIT_FINISHING_STATE = 0x08;
// private static int SETDICT_FINISHING_STATE = 0x09;
private const int BUSY_STATE = 0x10;
private const int FLUSHING_STATE = 0x14;
private const int FINISHING_STATE = 0x1c;
private const int FINISHED_STATE = 0x1e;
private const int CLOSED_STATE = 0x7f;
#endregion
#region Constructors
/// <summary>
/// Creates a new deflater with default compression level.
/// </summary>
public Deflater()
: this(DEFAULT_COMPRESSION, false)
{
}
/// <summary>
/// Creates a new deflater with given compression level.
/// </summary>
/// <param name="level">
/// the compression level, a value between NO_COMPRESSION
/// and BEST_COMPRESSION, or DEFAULT_COMPRESSION.
/// </param>
/// <exception cref="System.ArgumentOutOfRangeException">if lvl is out of range.</exception>
public Deflater(int level)
: this(level, false)
{
}
/// <summary>
/// Creates a new deflater with given compression level.
/// </summary>
/// <param name="level">
/// the compression level, a value between NO_COMPRESSION
/// and BEST_COMPRESSION.
/// </param>
/// <param name="noZlibHeaderOrFooter">
/// true, if we should suppress the Zlib/RFC1950 header at the
/// beginning and the adler checksum at the end of the output. This is
/// useful for the GZIP/PKZIP formats.
/// </param>
/// <exception cref="System.ArgumentOutOfRangeException">if lvl is out of range.</exception>
public Deflater(int level, bool noZlibHeaderOrFooter)
{
if (level == DEFAULT_COMPRESSION)
{
level = 6;
}
else if (level < NO_COMPRESSION || level > BEST_COMPRESSION)
{
throw new ArgumentOutOfRangeException("level");
}
pending = new DeflaterPending();
engine = new DeflaterEngine(pending);
this.noZlibHeaderOrFooter = noZlibHeaderOrFooter;
SetStrategy(DeflateStrategy.Default);
SetLevel(level);
Reset();
}
#endregion
/// <summary>
/// Resets the deflater. The deflater acts afterwards as if it was
/// just created with the same compression level and strategy as it
/// had before.
/// </summary>
public void Reset()
{
state = (noZlibHeaderOrFooter ? BUSY_STATE : INIT_STATE);
totalOut = 0;
pending.Reset();
engine.Reset();
}
/// <summary>
/// Gets the current adler checksum of the data that was processed so far.
/// </summary>
public int Adler
{
get
{
return engine.Adler;
}
}
/// <summary>
/// Gets the number of input bytes processed so far.
/// </summary>
public long TotalIn
{
get
{
return engine.TotalIn;
}
}
/// <summary>
/// Gets the number of output bytes so far.
/// </summary>
public long TotalOut
{
get
{
return totalOut;
}
}
/// <summary>
/// Flushes the current input block. Further calls to deflate() will
/// produce enough output to inflate everything in the current input
/// block. This is not part of Sun's JDK so I have made it package
/// private. It is used by DeflaterOutputStream to implement
/// flush().
/// </summary>
public void Flush()
{
state |= IS_FLUSHING;
}
/// <summary>
/// Finishes the deflater with the current input block. It is an error
/// to give more input after this method was called. This method must
/// be called to force all bytes to be flushed.
/// </summary>
public void Finish()
{
state |= (IS_FLUSHING | IS_FINISHING);
}
/// <summary>
/// Returns true if the stream was finished and no more output bytes
/// are available.
/// </summary>
public bool IsFinished
{
get
{
return (state == FINISHED_STATE) && pending.IsFlushed;
}
}
/// <summary>
/// Returns true, if the input buffer is empty.
/// You should then call setInput().
/// NOTE: This method can also return true when the stream
/// was finished.
/// </summary>
public bool IsNeedingInput
{
get
{
return engine.NeedsInput();
}
}
/// <summary>
/// Sets the data which should be compressed next. This should be only
/// called when needsInput indicates that more input is needed.
/// If you call setInput when needsInput() returns false, the
/// previous input that is still pending will be thrown away.
/// The given byte array should not be changed, before needsInput() returns
/// true again.
/// This call is equivalent to <code>setInput(input, 0, input.length)</code>.
/// </summary>
/// <param name="input">
/// the buffer containing the input data.
/// </param>
/// <exception cref="System.InvalidOperationException">
/// if the buffer was finished() or ended().
/// </exception>
public void SetInput(byte[] input)
{
SetInput(input, 0, input.Length);
}
/// <summary>
/// Sets the data which should be compressed next. This should be
/// only called when needsInput indicates that more input is needed.
/// The given byte array should not be changed, before needsInput() returns
/// true again.
/// </summary>
/// <param name="input">
/// the buffer containing the input data.
/// </param>
/// <param name="offset">
/// the start of the data.
/// </param>
/// <param name="count">
/// the number of data bytes of input.
/// </param>
/// <exception cref="System.InvalidOperationException">
/// if the buffer was Finish()ed or if previous input is still pending.
/// </exception>
public void SetInput(byte[] input, int offset, int count)
{
if ((state & IS_FINISHING) != 0)
{
throw new InvalidOperationException("Finish() already called");
}
engine.SetInput(input, offset, count);
}
/// <summary>
/// Sets the compression level. There is no guarantee of the exact
/// position of the change, but if you call this when needsInput is
/// true the change of compression level will occur somewhere near
/// before the end of the so far given input.
/// </summary>
/// <param name="level">
/// the new compression level.
/// </param>
public void SetLevel(int level)
{
if (level == DEFAULT_COMPRESSION)
{
level = 6;
}
else if (level < NO_COMPRESSION || level > BEST_COMPRESSION)
{
throw new ArgumentOutOfRangeException("level");
}
if (this.level != level)
{
this.level = level;
engine.SetLevel(level);
}
}
/// <summary>
/// Get current compression level
/// </summary>
/// <returns>Returns the current compression level</returns>
public int GetLevel()
{
return level;
}
/// <summary>
/// Sets the compression strategy. Strategy is one of
/// DEFAULT_STRATEGY, HUFFMAN_ONLY and FILTERED. For the exact
/// position where the strategy is changed, the same as for
/// SetLevel() applies.
/// </summary>
/// <param name="strategy">
/// The new compression strategy.
/// </param>
public void SetStrategy(DeflateStrategy strategy)
{
engine.Strategy = strategy;
}
/// <summary>
/// Deflates the current input block with to the given array.
/// </summary>
/// <param name="output">
/// The buffer where compressed data is stored
/// </param>
/// <returns>
/// The number of compressed bytes added to the output, or 0 if either
/// IsNeedingInput() or IsFinished returns true or length is zero.
/// </returns>
public int Deflate(byte[] output)
{
return Deflate(output, 0, output.Length);
}
/// <summary>
/// Deflates the current input block to the given array.
/// </summary>
/// <param name="output">
/// Buffer to store the compressed data.
/// </param>
/// <param name="offset">
/// Offset into the output array.
/// </param>
/// <param name="length">
/// The maximum number of bytes that may be stored.
/// </param>
/// <returns>
/// The number of compressed bytes added to the output, or 0 if either
/// needsInput() or finished() returns true or length is zero.
/// </returns>
/// <exception cref="System.InvalidOperationException">
/// If Finish() was previously called.
/// </exception>
/// <exception cref="System.ArgumentOutOfRangeException">
/// If offset or length don't match the array length.
/// </exception>
public int Deflate(byte[] output, int offset, int length)
{
int origLength = length;
if (state == CLOSED_STATE)
{
throw new InvalidOperationException("Deflater closed");
}
if (state < BUSY_STATE)
{
// output header
int header = (DEFLATED +
((DeflaterConstants.MAX_WBITS - 8) << 4)) << 8;
int level_flags = (level - 1) >> 1;
if (level_flags < 0 || level_flags > 3)
{
level_flags = 3;
}
header |= level_flags << 6;
if ((state & IS_SETDICT) != 0)
{
// Dictionary was set
header |= DeflaterConstants.PRESET_DICT;
}
header += 31 - (header % 31);
pending.WriteShortMSB(header);
if ((state & IS_SETDICT) != 0)
{
int chksum = engine.Adler;
engine.ResetAdler();
pending.WriteShortMSB(chksum >> 16);
pending.WriteShortMSB(chksum & 0xffff);
}
state = BUSY_STATE | (state & (IS_FLUSHING | IS_FINISHING));
}
for (; ; )
{
int count = pending.Flush(output, offset, length);
offset += count;
totalOut += count;
length -= count;
if (length == 0 || state == FINISHED_STATE)
{
break;
}
if (!engine.Deflate((state & IS_FLUSHING) != 0, (state & IS_FINISHING) != 0))
{
if (state == BUSY_STATE)
{
// We need more input now
return origLength - length;
}
else if (state == FLUSHING_STATE)
{
if (level != NO_COMPRESSION)
{
/* We have to supply some lookahead. 8 bit lookahead
* is needed by the zlib inflater, and we must fill
* the next byte, so that all bits are flushed.
*/
int neededbits = 8 + ((-pending.BitCount) & 7);
while (neededbits > 0)
{
/* write a static tree block consisting solely of
* an EOF:
*/
pending.WriteBits(2, 10);
neededbits -= 10;
}
}
state = BUSY_STATE;
}
else if (state == FINISHING_STATE)
{
pending.AlignToByte();
// Compressed data is complete. Write footer information if required.
if (!noZlibHeaderOrFooter)
{
int adler = engine.Adler;
pending.WriteShortMSB(adler >> 16);
pending.WriteShortMSB(adler & 0xffff);
}
state = FINISHED_STATE;
}
}
}
return origLength - length;
}
/// <summary>
/// Sets the dictionary which should be used in the deflate process.
/// This call is equivalent to <code>setDictionary(dict, 0, dict.Length)</code>.
/// </summary>
/// <param name="dictionary">
/// the dictionary.
/// </param>
/// <exception cref="System.InvalidOperationException">
/// if SetInput () or Deflate () were already called or another dictionary was already set.
/// </exception>
public void SetDictionary(byte[] dictionary)
{
SetDictionary(dictionary, 0, dictionary.Length);
}
/// <summary>
/// Sets the dictionary which should be used in the deflate process.
/// The dictionary is a byte array containing strings that are
/// likely to occur in the data which should be compressed. The
/// dictionary is not stored in the compressed output, only a
/// checksum. To decompress the output you need to supply the same
/// dictionary again.
/// </summary>
/// <param name="dictionary">
/// The dictionary data
/// </param>
/// <param name="index">
/// The index where dictionary information commences.
/// </param>
/// <param name="count">
/// The number of bytes in the dictionary.
/// </param>
/// <exception cref="System.InvalidOperationException">
/// If SetInput () or Deflate() were already called or another dictionary was already set.
/// </exception>
public void SetDictionary(byte[] dictionary, int index, int count)
{
if (state != INIT_STATE)
{
throw new InvalidOperationException();
}
state = SETDICT_STATE;
engine.SetDictionary(dictionary, index, count);
}
#region Instance Fields
/// <summary>
/// Compression level.
/// </summary>
int level;
/// <summary>
/// If true no Zlib/RFC1950 headers or footers are generated
/// </summary>
bool noZlibHeaderOrFooter;
/// <summary>
/// The current state.
/// </summary>
int state;
/// <summary>
/// The total bytes of output written.
/// </summary>
long totalOut;
/// <summary>
/// The pending output.
/// </summary>
DeflaterPending pending;
/// <summary>
/// The deflater engine.
/// </summary>
DeflaterEngine engine;
#endregion
}
#endregion
#region OutputWindow
/// <summary>
/// Contains the output from the Inflation process.
/// We need to have a window so that we can refer backwards into the output stream
/// to repeat stuff.<br/>
/// Author of the original java version : John Leuner
/// </summary>
internal class OutputWindow
{
#region Constants
const int WindowSize = 1 << 15;
const int WindowMask = WindowSize - 1;
#endregion
#region Instance Fields
byte[] window = new byte[WindowSize]; //The window is 2^15 bytes
int windowEnd;
int windowFilled;
#endregion
/// <summary>
/// Write a byte to this output window
/// </summary>
/// <param name="value">value to write</param>
/// <exception cref="InvalidOperationException">
/// if window is full
/// </exception>
public void Write(int value)
{
if (windowFilled++ == WindowSize)
{
throw new InvalidOperationException("Window full");
}
window[windowEnd++] = (byte)value;
windowEnd &= WindowMask;
}
private void SlowRepeat(int repStart, int length, int distance)
{
while (length-- > 0)
{
window[windowEnd++] = window[repStart++];
windowEnd &= WindowMask;
repStart &= WindowMask;
}
}
/// <summary>
/// Append a byte pattern already in the window itself
/// </summary>
/// <param name="length">length of pattern to copy</param>
/// <param name="distance">distance from end of window pattern occurs</param>
/// <exception cref="InvalidOperationException">
/// If the repeated data overflows the window
/// </exception>
public void Repeat(int length, int distance)
{
if ((windowFilled += length) > WindowSize)
{
throw new InvalidOperationException("Window full");
}
int repStart = (windowEnd - distance) & WindowMask;
int border = WindowSize - length;
if ((repStart <= border) && (windowEnd < border))
{
if (length <= distance)
{
System.Array.Copy(window, repStart, window, windowEnd, length);
windowEnd += length;
}
else
{
// We have to copy manually, since the repeat pattern overlaps.
while (length-- > 0)
{
window[windowEnd++] = window[repStart++];
}
}
}
else
{
SlowRepeat(repStart, length, distance);
}
}
/// <summary>
/// Copy from input manipulator to internal window
/// </summary>
/// <param name="input">source of data</param>
/// <param name="length">length of data to copy</param>
/// <returns>the number of bytes copied</returns>
public int CopyStored(StreamManipulator input, int length)
{
length = Math.Min(Math.Min(length, WindowSize - windowFilled), input.AvailableBytes);
int copied;
int tailLen = WindowSize - windowEnd;
if (length > tailLen)
{
copied = input.CopyBytes(window, windowEnd, tailLen);
if (copied == tailLen)
{
copied += input.CopyBytes(window, 0, length - tailLen);
}
}
else
{
copied = input.CopyBytes(window, windowEnd, length);
}
windowEnd = (windowEnd + copied) & WindowMask;
windowFilled += copied;
return copied;
}
/// <summary>
/// Copy dictionary to window
/// </summary>
/// <param name="dictionary">source dictionary</param>
/// <param name="offset">offset of start in source dictionary</param>
/// <param name="length">length of dictionary</param>
/// <exception cref="InvalidOperationException">
/// If window isnt empty
/// </exception>
public void CopyDict(byte[] dictionary, int offset, int length)
{
if (dictionary == null)
{
throw new ArgumentNullException("dictionary");
}
if (windowFilled > 0)
{
throw new InvalidOperationException();
}
if (length > WindowSize)
{
offset += length - WindowSize;
length = WindowSize;
}
System.Array.Copy(dictionary, offset, window, 0, length);
windowEnd = length & WindowMask;
}
/// <summary>
/// Get remaining unfilled space in window
/// </summary>
/// <returns>Number of bytes left in window</returns>
public int GetFreeSpace()
{
return WindowSize - windowFilled;
}
/// <summary>
/// Get bytes available for output in window
/// </summary>
/// <returns>Number of bytes filled</returns>
public int GetAvailable()
{
return windowFilled;
}
/// <summary>
/// Copy contents of window to output
/// </summary>
/// <param name="output">buffer to copy to</param>
/// <param name="offset">offset to start at</param>
/// <param name="len">number of bytes to count</param>
/// <returns>The number of bytes copied</returns>
/// <exception cref="InvalidOperationException">
/// If a window underflow occurs
/// </exception>
public int CopyOutput(byte[] output, int offset, int len)
{
int copyEnd = windowEnd;
if (len > windowFilled)
{
len = windowFilled;
}
else
{
copyEnd = (windowEnd - windowFilled + len) & WindowMask;
}
int copied = len;
int tailLen = len - copyEnd;
if (tailLen > 0)
{
System.Array.Copy(window, WindowSize - tailLen, output, offset, tailLen);
offset += tailLen;
len = copyEnd;
}
System.Array.Copy(window, copyEnd - len, output, offset, len);
windowFilled -= copied;
if (windowFilled < 0)
{
throw new InvalidOperationException();
}
return copied;
}
/// <summary>
/// Reset by clearing window so <see cref="GetAvailable">GetAvailable</see> returns 0
/// </summary>
public void Reset()
{
windowFilled = windowEnd = 0;
}
}
#endregion
#region Inflater
/// <summary>
/// Inflater is used to decompress data that has been compressed according
/// to the "deflate" standard described in rfc1951.
///
/// By default Zlib (rfc1950) headers and footers are expected in the input.
/// You can use constructor <code> public Inflater(bool noHeader)</code> passing true
/// if there is no Zlib header information
///
/// The usage is as following. First you have to set some input with
/// <code>SetInput()</code>, then Inflate() it. If inflate doesn't
/// inflate any bytes there may be three reasons:
/// <ul>
/// <li>IsNeedingInput() returns true because the input buffer is empty.
/// You have to provide more input with <code>SetInput()</code>.
/// NOTE: IsNeedingInput() also returns true when, the stream is finished.
/// </li>
/// <li>IsNeedingDictionary() returns true, you have to provide a preset
/// dictionary with <code>SetDictionary()</code>.</li>
/// <li>IsFinished returns true, the inflater has finished.</li>
/// </ul>
/// Once the first output byte is produced, a dictionary will not be
/// needed at a later stage.
///
/// author of the original java version : John Leuner, Jochen Hoenicke
/// </summary>
internal class Inflater
{
#region Constants/Readonly
/// <summary>
/// Copy lengths for literal codes 257..285
/// </summary>
static readonly int[] CPLENS = {
3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258
};
/// <summary>
/// Extra bits for literal codes 257..285
/// </summary>
static readonly int[] CPLEXT = {
0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0
};
/// <summary>
/// Copy offsets for distance codes 0..29
/// </summary>
static readonly int[] CPDIST = {
1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
8193, 12289, 16385, 24577
};
/// <summary>
/// Extra bits for distance codes
/// </summary>
static readonly int[] CPDEXT = {
0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
12, 12, 13, 13
};
/// <summary>
/// These are the possible states for an inflater
/// </summary>
const int DECODE_HEADER = 0;
const int DECODE_DICT = 1;
const int DECODE_BLOCKS = 2;
const int DECODE_STORED_LEN1 = 3;
const int DECODE_STORED_LEN2 = 4;
const int DECODE_STORED = 5;
const int DECODE_DYN_HEADER = 6;
const int DECODE_HUFFMAN = 7;
const int DECODE_HUFFMAN_LENBITS = 8;
const int DECODE_HUFFMAN_DIST = 9;
const int DECODE_HUFFMAN_DISTBITS = 10;
const int DECODE_CHKSUM = 11;
const int FINISHED = 12;
#endregion
#region Instance Fields
/// <summary>
/// This variable contains the current state.
/// </summary>
int mode;
/// <summary>
/// The adler checksum of the dictionary or of the decompressed
/// stream, as it is written in the header resp. footer of the
/// compressed stream.
/// Only valid if mode is DECODE_DICT or DECODE_CHKSUM.
/// </summary>
int readAdler;
/// <summary>
/// The number of bits needed to complete the current state. This
/// is valid, if mode is DECODE_DICT, DECODE_CHKSUM,
/// DECODE_HUFFMAN_LENBITS or DECODE_HUFFMAN_DISTBITS.
/// </summary>
int neededBits;
int repLength;
int repDist;
int uncomprLen;
/// <summary>
/// True, if the last block flag was set in the last block of the
/// inflated stream. This means that the stream ends after the
/// current block.
/// </summary>
bool isLastBlock;
/// <summary>
/// The total number of inflated bytes.
/// </summary>
long totalOut;
/// <summary>
/// The total number of bytes set with setInput(). This is not the
/// value returned by the TotalIn property, since this also includes the
/// unprocessed input.
/// </summary>
long totalIn;
/// <summary>
/// This variable stores the noHeader flag that was given to the constructor.
/// True means, that the inflated stream doesn't contain a Zlib header or
/// footer.
/// </summary>
bool noHeader;
StreamManipulator input;
OutputWindow outputWindow;
InflaterDynHeader dynHeader;
InflaterHuffmanTree litlenTree, distTree;
//Adler32 adler;
#endregion
#region Constructors
/// <summary>
/// Creates a new inflater or RFC1951 decompressor
/// RFC1950/Zlib headers and footers will be expected in the input data
/// </summary>
public Inflater()
: this(false)
{
}
/// <summary>
/// Creates a new inflater.
/// </summary>
/// <param name="noHeader">
/// True if no RFC1950/Zlib header and footer fields are expected in the input data
///
/// This is used for GZIPed/Zipped input.
///
/// For compatibility with
/// Sun JDK you should provide one byte of input more than needed in
/// this case.
/// </param>
public Inflater(bool noHeader)
{
this.noHeader = noHeader;
//this.adler = new Adler32();
input = new StreamManipulator();
outputWindow = new OutputWindow();
mode = noHeader ? DECODE_BLOCKS : DECODE_HEADER;
}
#endregion
/// <summary>
/// Resets the inflater so that a new stream can be decompressed. All
/// pending input and output will be discarded.
/// </summary>
public void Reset()
{
mode = noHeader ? DECODE_BLOCKS : DECODE_HEADER;
totalIn = 0;
totalOut = 0;
input.Reset();
outputWindow.Reset();
dynHeader = null;
litlenTree = null;
distTree = null;
isLastBlock = false;
//adler.Reset();
}
/// <summary>
/// Decodes a zlib/RFC1950 header.
/// </summary>
/// <returns>
/// False if more input is needed.
/// </returns>
/// <exception cref="SharpZipBaseException">
/// The header is invalid.
/// </exception>
private bool DecodeHeader()
{
int header = input.PeekBits(16);
if (header < 0)
{
return false;
}
input.DropBits(16);
// The header is written in "wrong" byte order
header = ((header << 8) | (header >> 8)) & 0xffff;
if (header % 31 != 0)
{
throw new Exception("Header checksum illegal");
}
if ((header & 0x0f00) != (Deflater.DEFLATED << 8))
{
throw new Exception("Compression Method unknown");
}
/* Maximum size of the backwards window in bits.
* We currently ignore this, but we could use it to make the
* inflater window more space efficient. On the other hand the
* full window (15 bits) is needed most times, anyway.
int max_wbits = ((header & 0x7000) >> 12) + 8;
*/
if ((header & 0x0020) == 0)
{ // Dictionary flag?
mode = DECODE_BLOCKS;
}
else
{
mode = DECODE_DICT;
neededBits = 32;
}
return true;
}
/// <summary>
/// Decodes the dictionary checksum after the deflate header.
/// </summary>
/// <returns>
/// False if more input is needed.
/// </returns>
private bool DecodeDict()
{
while (neededBits > 0)
{
int dictByte = input.PeekBits(8);
if (dictByte < 0)
{
return false;
}
input.DropBits(8);
readAdler = (readAdler << 8) | dictByte;
neededBits -= 8;
}
return false;
}
/// <summary>
/// Decodes the huffman encoded symbols in the input stream.
/// </summary>
/// <returns>
/// false if more input is needed, true if output window is
/// full or the current block ends.
/// </returns>
/// <exception cref="SharpZipBaseException">
/// if deflated stream is invalid.
/// </exception>
private bool DecodeHuffman()
{
int free = outputWindow.GetFreeSpace();
while (free >= 258)
{
int symbol;
switch (mode)
{
case DECODE_HUFFMAN:
// This is the inner loop so it is optimized a bit
while (((symbol = litlenTree.GetSymbol(input)) & ~0xff) == 0)
{
outputWindow.Write(symbol);
if (--free < 258)
{
return true;
}
}
if (symbol < 257)
{
if (symbol < 0)
{
return false;
}
else
{
// symbol == 256: end of block
distTree = null;
litlenTree = null;
mode = DECODE_BLOCKS;
return true;
}
}
try
{
repLength = CPLENS[symbol - 257];
neededBits = CPLEXT[symbol - 257];
}
catch (Exception)
{
throw new Exception("Illegal rep length code");
}
goto case DECODE_HUFFMAN_LENBITS; // fall through
case DECODE_HUFFMAN_LENBITS:
if (neededBits > 0)
{
mode = DECODE_HUFFMAN_LENBITS;
int i = input.PeekBits(neededBits);
if (i < 0)
{
return false;
}
input.DropBits(neededBits);
repLength += i;
}
mode = DECODE_HUFFMAN_DIST;
goto case DECODE_HUFFMAN_DIST; // fall through
case DECODE_HUFFMAN_DIST:
symbol = distTree.GetSymbol(input);
if (symbol < 0)
{
return false;
}
try
{
repDist = CPDIST[symbol];
neededBits = CPDEXT[symbol];
}
catch (Exception)
{
throw new Exception("Illegal rep dist code");
}
goto case DECODE_HUFFMAN_DISTBITS; // fall through
case DECODE_HUFFMAN_DISTBITS:
if (neededBits > 0)
{
mode = DECODE_HUFFMAN_DISTBITS;
int i = input.PeekBits(neededBits);
if (i < 0)
{
return false;
}
input.DropBits(neededBits);
repDist += i;
}
outputWindow.Repeat(repLength, repDist);
free -= repLength;
mode = DECODE_HUFFMAN;
break;
default:
throw new Exception("Inflater unknown mode");
}
}
return true;
}
/// <summary>
/// Decodes the adler checksum after the deflate stream.
/// </summary>
/// <returns>
/// false if more input is needed.
/// </returns>
/// <exception cref="SharpZipBaseException">
/// If checksum doesn't match.
/// </exception>
private bool DecodeChksum()
{
while (neededBits > 0)
{
int chkByte = input.PeekBits(8);
if (chkByte < 0)
{
return false;
}
input.DropBits(8);
readAdler = (readAdler << 8) | chkByte;
neededBits -= 8;
}
//if ((int)adler.Value != readAdler)
//{
// throw new Exception("Adler chksum doesn't match: " + (int)adler.Value + " vs. " + readAdler);
//}
mode = FINISHED;
return false;
}
/// <summary>
/// Decodes the deflated stream.
/// </summary>
/// <returns>
/// false if more input is needed, or if finished.
/// </returns>
/// <exception cref="SharpZipBaseException">
/// if deflated stream is invalid.
/// </exception>
private bool Decode()
{
switch (mode)
{
case DECODE_HEADER:
return DecodeHeader();
case DECODE_DICT:
return DecodeDict();
case DECODE_CHKSUM:
return DecodeChksum();
case DECODE_BLOCKS:
if (isLastBlock)
{
if (noHeader)
{
mode = FINISHED;
return false;
}
else
{
input.SkipToByteBoundary();
neededBits = 32;
mode = DECODE_CHKSUM;
return true;
}
}
int type = input.PeekBits(3);
if (type < 0)
{
return false;
}
input.DropBits(3);
if ((type & 1) != 0)
{
isLastBlock = true;
}
switch (type >> 1)
{
case DeflaterConstants.STORED_BLOCK:
input.SkipToByteBoundary();
mode = DECODE_STORED_LEN1;
break;
case DeflaterConstants.STATIC_TREES:
litlenTree = InflaterHuffmanTree.defLitLenTree;
distTree = InflaterHuffmanTree.defDistTree;
mode = DECODE_HUFFMAN;
break;
case DeflaterConstants.DYN_TREES:
dynHeader = new InflaterDynHeader();
mode = DECODE_DYN_HEADER;
break;
default:
throw new Exception("Unknown block type " + type);
}
return true;
case DECODE_STORED_LEN1:
{
if ((uncomprLen = input.PeekBits(16)) < 0)
{
return false;
}
input.DropBits(16);
mode = DECODE_STORED_LEN2;
}
goto case DECODE_STORED_LEN2; // fall through
case DECODE_STORED_LEN2:
{
int nlen = input.PeekBits(16);
if (nlen < 0)
{
return false;
}
input.DropBits(16);
if (nlen != (uncomprLen ^ 0xffff))
{
throw new Exception("broken uncompressed block");
}
mode = DECODE_STORED;
}
goto case DECODE_STORED; // fall through
case DECODE_STORED:
{
int more = outputWindow.CopyStored(input, uncomprLen);
uncomprLen -= more;
if (uncomprLen == 0)
{
mode = DECODE_BLOCKS;
return true;
}
return !input.IsNeedingInput;
}
case DECODE_DYN_HEADER:
if (!dynHeader.Decode(input))
{
return false;
}
litlenTree = dynHeader.BuildLitLenTree();
distTree = dynHeader.BuildDistTree();
mode = DECODE_HUFFMAN;
goto case DECODE_HUFFMAN; // fall through
case DECODE_HUFFMAN:
case DECODE_HUFFMAN_LENBITS:
case DECODE_HUFFMAN_DIST:
case DECODE_HUFFMAN_DISTBITS:
return DecodeHuffman();
case FINISHED:
return false;
default:
throw new Exception("Inflater.Decode unknown mode");
}
}
/// <summary>
/// Sets the preset dictionary. This should only be called, if
/// needsDictionary() returns true and it should set the same
/// dictionary, that was used for deflating. The getAdler()
/// function returns the checksum of the dictionary needed.
/// </summary>
/// <param name="buffer">
/// The dictionary.
/// </param>
public void SetDictionary(byte[] buffer)
{
SetDictionary(buffer, 0, buffer.Length);
}
/// <summary>
/// Sets the preset dictionary. This should only be called, if
/// needsDictionary() returns true and it should set the same
/// dictionary, that was used for deflating. The getAdler()
/// function returns the checksum of the dictionary needed.
/// </summary>
/// <param name="buffer">
/// The dictionary.
/// </param>
/// <param name="index">
/// The index into buffer where the dictionary starts.
/// </param>
/// <param name="count">
/// The number of bytes in the dictionary.
/// </param>
/// <exception cref="System.InvalidOperationException">
/// No dictionary is needed.
/// </exception>
/// <exception cref="SharpZipBaseException">
/// The adler checksum for the buffer is invalid
/// </exception>
public void SetDictionary(byte[] buffer, int index, int count)
{
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
if (index < 0)
{
throw new ArgumentOutOfRangeException("index");
}
if (count < 0)
{
throw new ArgumentOutOfRangeException("count");
}
if (!IsNeedingDictionary)
{
throw new InvalidOperationException("Dictionary is not needed");
}
//adler.Update(buffer, index, count);
//if ((int)adler.Value != readAdler)
//{
// throw new Exception("Wrong adler checksum");
//}
//adler.Reset();
outputWindow.CopyDict(buffer, index, count);
mode = DECODE_BLOCKS;
}
/// <summary>
/// Sets the input. This should only be called, if needsInput()
/// returns true.
/// </summary>
/// <param name="buffer">
/// the input.
/// </param>
public void SetInput(byte[] buffer)
{
SetInput(buffer, 0, buffer.Length);
}
/// <summary>
/// Sets the input. This should only be called, if needsInput()
/// returns true.
/// </summary>
/// <param name="buffer">
/// The source of input data
/// </param>
/// <param name="index">
/// The index into buffer where the input starts.
/// </param>
/// <param name="count">
/// The number of bytes of input to use.
/// </param>
/// <exception cref="System.InvalidOperationException">
/// No input is needed.
/// </exception>
/// <exception cref="System.ArgumentOutOfRangeException">
/// The index and/or count are wrong.
/// </exception>
public void SetInput(byte[] buffer, int index, int count)
{
input.SetInput(buffer, index, count);
totalIn += (long)count;
}
/// <summary>
/// Inflates the compressed stream to the output buffer. If this
/// returns 0, you should check, whether IsNeedingDictionary(),
/// IsNeedingInput() or IsFinished() returns true, to determine why no
/// further output is produced.
/// </summary>
/// <param name="buffer">
/// the output buffer.
/// </param>
/// <returns>
/// The number of bytes written to the buffer, 0 if no further
/// output can be produced.
/// </returns>
/// <exception cref="System.ArgumentOutOfRangeException">
/// if buffer has length 0.
/// </exception>
/// <exception cref="System.FormatException">
/// if deflated stream is invalid.
/// </exception>
public int Inflate(byte[] buffer)
{
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
return Inflate(buffer, 0, buffer.Length);
}
/// <summary>
/// Inflates the compressed stream to the output buffer. If this
/// returns 0, you should check, whether needsDictionary(),
/// needsInput() or finished() returns true, to determine why no
/// further output is produced.
/// </summary>
/// <param name="buffer">
/// the output buffer.
/// </param>
/// <param name="offset">
/// the offset in buffer where storing starts.
/// </param>
/// <param name="count">
/// the maximum number of bytes to output.
/// </param>
/// <returns>
/// the number of bytes written to the buffer, 0 if no further output can be produced.
/// </returns>
/// <exception cref="System.ArgumentOutOfRangeException">
/// if count is less than 0.
/// </exception>
/// <exception cref="System.ArgumentOutOfRangeException">
/// if the index and / or count are wrong.
/// </exception>
/// <exception cref="System.FormatException">
/// if deflated stream is invalid.
/// </exception>
public int Inflate(byte[] buffer, int offset, int count)
{
//if (buffer == null)
//{
// throw new ArgumentNullException("buffer");
//}
//if (count < 0)
//{
// throw new ArgumentOutOfRangeException("count", "count cannot be negative");
//}
//if (offset < 0)
//{
// throw new ArgumentOutOfRangeException("offset", "offset cannot be negative");
//}
//if (offset + count > buffer.Length)
//{
// throw new ArgumentException("count exceeds buffer bounds");
//}
// Special case: count may be zero
if (count == 0)
{
if (!IsFinished)
{ // -jr- 08-Nov-2003 INFLATE_BUG fix..
Decode();
}
return 0;
}
int bytesCopied = 0;
do
{
if (mode != DECODE_CHKSUM)
{
/* Don't give away any output, if we are waiting for the
* checksum in the input stream.
*
* With this trick we have always:
* IsNeedingInput() and not IsFinished()
* implies more output can be produced.
*/
int more = outputWindow.CopyOutput(buffer, offset, count);
if (more > 0)
{
//adler.Update(buffer, offset, more);
offset += more;
bytesCopied += more;
totalOut += (long)more;
count -= more;
if (count == 0)
{
return bytesCopied;
}
}
}
} while (Decode() || ((outputWindow.GetAvailable() > 0) && (mode != DECODE_CHKSUM)));
return bytesCopied;
}
/// <summary>
/// Returns true, if the input buffer is empty.
/// You should then call setInput().
/// NOTE: This method also returns true when the stream is finished.
/// </summary>
public bool IsNeedingInput
{
get
{
return input.IsNeedingInput;
}
}
/// <summary>
/// Returns true, if a preset dictionary is needed to inflate the input.
/// </summary>
public bool IsNeedingDictionary
{
get
{
return mode == DECODE_DICT && neededBits == 0;
}
}
/// <summary>
/// Returns true, if the inflater has finished. This means, that no
/// input is needed and no output can be produced.
/// </summary>
public bool IsFinished
{
get
{
return mode == FINISHED && outputWindow.GetAvailable() == 0;
}
}
///// <summary>
///// Gets the adler checksum. This is either the checksum of all
///// uncompressed bytes returned by inflate(), or if needsDictionary()
///// returns true (and thus no output was yet produced) this is the
///// adler checksum of the expected dictionary.
///// </summary>
///// <returns>
///// the adler checksum.
///// </returns>
//public int Adler
//{
// get
// {
// return IsNeedingDictionary ? readAdler : (int)adler.Value;
// }
//}
/// <summary>
/// Gets the total number of output bytes returned by Inflate().
/// </summary>
/// <returns>
/// the total number of output bytes.
/// </returns>
public long TotalOut
{
get
{
return totalOut;
}
}
/// <summary>
/// Gets the total number of processed compressed input bytes.
/// </summary>
/// <returns>
/// The total number of bytes of processed input bytes.
/// </returns>
public long TotalIn
{
get
{
return totalIn - (long)RemainingInput;
}
}
/// <summary>
/// Gets the number of unprocessed input bytes. Useful, if the end of the
/// stream is reached and you want to further process the bytes after
/// the deflate stream.
/// </summary>
/// <returns>
/// The number of bytes of the input which have not been processed.
/// </returns>
public int RemainingInput
{
// TODO: This should be a long?
get
{
return input.AvailableBytes;
}
}
}
#endregion
#region InflaterInputBuffer
/// <summary>
/// An input buffer customised for use by <see cref="DeflaterInputStream"/>
/// </summary>
/// <remarks>
/// The buffer supports decryption of incoming data.
/// </remarks>
internal class InflaterInputBuffer
{
/// <summary>
/// Initialise a new instance of <see cref="InflaterInputBuffer"/> with a default buffer size
/// </summary>
/// <param name="stream">The stream to buffer.</param>
public InflaterInputBuffer(Stream stream)
: this(stream, 4096)
{
}
/// <summary>
/// Initialise a new instance of <see cref="InflaterInputBuffer"/>
/// </summary>
/// <param name="stream">The stream to buffer.</param>
/// <param name="bufferSize">The size to use for the buffer</param>
/// <remarks>A minimum buffer size of 1KB is permitted. Lower sizes are treated as 1KB.</remarks>
public InflaterInputBuffer(Stream stream, int bufferSize)
{
inputStream = stream;
if (bufferSize < 1024)
{
bufferSize = 1024;
}
rawData = new byte[bufferSize];
clearText = rawData;
}
/// <summary>
/// Get the length of bytes bytes in the <see cref="RawData"/>
/// </summary>
public int RawLength
{
get
{
return rawLength;
}
}
/// <summary>
/// Get the contents of the raw data buffer.
/// </summary>
/// <remarks>This may contain encrypted data.</remarks>
public byte[] RawData
{
get
{
return rawData;
}
}
/// <summary>
/// Get the number of useable bytes in <see cref="ClearText"/>
/// </summary>
public int ClearTextLength
{
get
{
return clearTextLength;
}
}
/// <summary>
/// Get the contents of the clear text buffer.
/// </summary>
public byte[] ClearText
{
get
{
return clearText;
}
}
/// <summary>
/// Get/set the number of bytes available
/// </summary>
public int Available
{
get { return available; }
set { available = value; }
}
/// <summary>
/// Call <see cref="Inflater.SetInput(byte[], int, int)"/> passing the current clear text buffer contents.
/// </summary>
/// <param name="inflater">The inflater to set input for.</param>
public void SetInflaterInput(Inflater inflater)
{
if (available > 0)
{
inflater.SetInput(clearText, clearTextLength - available, available);
available = 0;
}
}
/// <summary>
/// Fill the buffer from the underlying input stream.
/// </summary>
public void Fill()
{
rawLength = 0;
int toRead = rawData.Length;
while (toRead > 0)
{
int count = inputStream.Read(rawData, rawLength, toRead);
if (count <= 0)
{
break;
}
rawLength += count;
toRead -= count;
}
clearTextLength = rawLength;
available = clearTextLength;
}
/// <summary>
/// Read a buffer directly from the input stream
/// </summary>
/// <param name="buffer">The buffer to fill</param>
/// <returns>Returns the number of bytes read.</returns>
public int ReadRawBuffer(byte[] buffer)
{
return ReadRawBuffer(buffer, 0, buffer.Length);
}
/// <summary>
/// Read a buffer directly from the input stream
/// </summary>
/// <param name="outBuffer">The buffer to read into</param>
/// <param name="offset">The offset to start reading data into.</param>
/// <param name="length">The number of bytes to read.</param>
/// <returns>Returns the number of bytes read.</returns>
public int ReadRawBuffer(byte[] outBuffer, int offset, int length)
{
if (length < 0)
{
throw new ArgumentOutOfRangeException("length");
}
int currentOffset = offset;
int currentLength = length;
while (currentLength > 0)
{
if (available <= 0)
{
Fill();
if (available <= 0)
{
return 0;
}
}
int toCopy = Math.Min(currentLength, available);
System.Array.Copy(rawData, rawLength - (int)available, outBuffer, currentOffset, toCopy);
currentOffset += toCopy;
currentLength -= toCopy;
available -= toCopy;
}
return length;
}
/// <summary>
/// Read clear text data from the input stream.
/// </summary>
/// <param name="outBuffer">The buffer to add data to.</param>
/// <param name="offset">The offset to start adding data at.</param>
/// <param name="length">The number of bytes to read.</param>
/// <returns>Returns the number of bytes actually read.</returns>
public int ReadClearTextBuffer(byte[] outBuffer, int offset, int length)
{
if (length < 0)
{
throw new ArgumentOutOfRangeException("length");
}
int currentOffset = offset;
int currentLength = length;
while (currentLength > 0)
{
if (available <= 0)
{
Fill();
if (available <= 0)
{
return 0;
}
}
int toCopy = Math.Min(currentLength, available);
Array.Copy(clearText, clearTextLength - (int)available, outBuffer, currentOffset, toCopy);
currentOffset += toCopy;
currentLength -= toCopy;
available -= toCopy;
}
return length;
}
/// <summary>
/// Read a <see cref="byte"/> from the input stream.
/// </summary>
/// <returns>Returns the byte read.</returns>
public int ReadLeByte()
{
if (available <= 0)
{
Fill();
if (available <= 0)
{
throw new Exception("EOF in header");
}
}
byte result = rawData[rawLength - available];
available -= 1;
return result;
}
/// <summary>
/// Read an <see cref="short"/> in little endian byte order.
/// </summary>
/// <returns>The short value read case to an int.</returns>
public int ReadLeShort()
{
return ReadLeByte() | (ReadLeByte() << 8);
}
/// <summary>
/// Read an <see cref="int"/> in little endian byte order.
/// </summary>
/// <returns>The int value read.</returns>
public int ReadLeInt()
{
return ReadLeShort() | (ReadLeShort() << 16);
}
/// <summary>
/// Read a <see cref="long"/> in little endian byte order.
/// </summary>
/// <returns>The long value read.</returns>
public long ReadLeLong()
{
return (uint)ReadLeInt() | ((long)ReadLeInt() << 32);
}
#region Instance Fields
int rawLength;
byte[] rawData;
int clearTextLength;
byte[] clearText;
int available;
Stream inputStream;
#endregion
}
#endregion
}
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